docs: complete v0.5.0 administration, architecture and deployment guides

docs/ADMIN_GUIDE.md

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+# BZOD Administrator Guide
+
+Version: v0.5.0
+
+---
+
+# Introduction
+
+This guide is intended for BZOD administrators responsible for operating, maintaining, and managing a BZOD instance.
+
+It covers:
+
+* Administrator authentication
+* User management
+* Quotas
+* Sessions
+* Moderation
+* Slug ownership
+* Analytics
+* Audit logs
+* Backup and recovery
+* Health monitoring
+* Operational best practices
+
+---
+
+# Administrator Role
+
+Administrators have full platform control.
+
+Administrative capabilities include:
+
+* Create users
+* Modify users
+* Disable users
+* Delete users
+* Reset passwords
+* Manage quotas
+* Review analytics
+* Moderate content
+* Transfer slug ownership
+* Manage backups
+* Review audit logs
+* Monitor system health
+
+Administrators cannot bypass audit logging.
+
+All administrative actions are recorded.
+
+---
+
+# Login
+
+Administrative login is available at:
+
+```text
+/login
+```
+
+Successful login redirects to:
+
+```text
+/admin
+```
+
+Authentication uses:
+
+```text
+users.db
+```
+
+Sessions are stored in:
+
+```text
+users.db.sessions
+```
+
+Cookie name:
+
+```text
+bzod_session
+```
+
+---
+
+# Administrative Dashboard
+
+Route:
+
+```text
+/admin
+```
+
+The dashboard provides a high-level overview of platform activity.
+
+Metrics include:
+
+* Total Users
+* Active Users
+* Total URLs
+* Total Landing Pages
+* Active Sessions
+* API Tokens
+* Storage Usage
+* Moderation Events
+* Recent Audit Events
+
+Quick actions include:
+
+* Create User
+* View Sessions
+* View Audit Logs
+* Create Backup
+* Review Health Status
+
+---
+
+# User Management
+
+## Users List
+
+Route:
+
+```text
+/admin/users
+```
+
+Displays:
+
+* User ID
+* Username
+* Status
+* Account Type
+* Creation Date
+
+Available actions:
+
+* View
+* Edit
+* Disable
+* Enable
+* Reset Password
+* Delete
+
+---
+
+## Create User
+
+Route:
+
+```text
+/admin/users/new
+```
+
+Fields:
+
+* Username
+* Password
+* Account Type
+* Quota Limits
+
+Supported account types:
+
+```text
+admin
+standard
+```
+
+Reserved usernames cannot be used.
+
+Examples:
+
+```text
+admin
+legacy_admin
+system
+root
+administrator
+```
+
+---
+
+## User Detail Page
+
+Route:
+
+```text
+/admin/users/{id}
+```
+
+Displays:
+
+### Profile
+
+* User ID
+* Username
+* Status
+* Account Type
+* Created Date
+
+### Usage Statistics
+
+* URL Count
+* Landing Page Count
+* Visit Count
+* Storage Usage
+* API Token Count
+* Active Sessions
+
+### Quotas
+
+* Maximum URLs
+* Maximum Pages
+* Maximum Storage
+* Maximum Tokens
+
+### Sessions
+
+List of active sessions.
+
+### API Tokens
+
+List of active tokens.
+
+---
+
+## Edit User
+
+Route:
+
+```text
+/admin/users/{id}/edit
+```
+
+Administrators may:
+
+* Change status
+* Change account type
+* Modify quotas
+
+---
+
+## Reset Password
+
+Route:
+
+```text
+/admin/users/{id}/password
+```
+
+Creates a new password hash and invalidates existing sessions.
+
+Audit event generated:
+
+```text
+password_reset
+```
+
+---
+
+## Disable User
+
+Route:
+
+```text
+/admin/users/{id}/disable
+```
+
+Effects:
+
+* User login disabled
+* Existing sessions revoked
+* API access denied
+
+Audit event generated:
+
+```text
+user_disabled
+```
+
+---
+
+## Enable User
+
+Route:
+
+```text
+/admin/users/{id}/enable
+```
+
+Restores account access.
+
+Audit event generated:
+
+```text
+user_enabled
+```
+
+---
+
+## Delete User
+
+Route:
+
+```text
+/admin/users/{id}/delete
+```
+
+Deletion performs:
+
+1. Session revocation
+2. API token removal
+3. Content removal
+4. Analytics removal
+5. Slug release
+6. User database deletion
+
+Audit event generated:
+
+```text
+user_deleted
+```
+
+---
+
+# Session Management
+
+Route:
+
+```text
+/admin/sessions
+```
+
+Displays all active platform sessions.
+
+Information displayed:
+
+* User ID
+* Username
+* Session Identifier
+* Created Time
+* Expiry Time
+* IP Address
+* User Agent
+
+---
+
+## Revoke Session
+
+Individual sessions can be revoked.
+
+Effects:
+
+* Session removed immediately
+* User forced to reauthenticate
+
+---
+
+## Revoke All Sessions
+
+Administrators may invalidate all active sessions.
+
+Useful after:
+
+* Password compromise
+* Security incidents
+* Large configuration changes
+
+---
+
+# Quota Management
+
+Route:
+
+```text
+/admin/quotas
+```
+
+Quotas limit user resource consumption.
+
+Available limits:
+
+```text
+max_urls
+max_pages
+max_storage_mb
+max_api_tokens
+```
+
+---
+
+## Quota Reconciliation
+
+Administrators can execute:
+
+```text
+quota_reconcile
+```
+
+Purpose:
+
+* Detect counter drift
+* Recount resources
+* Repair quota usage
+
+Common causes:
+
+* Manual database modifications
+* Failed migrations
+* Interrupted operations
+
+---
+
+# Moderation
+
+Route:
+
+```text
+/admin/moderation
+```
+
+Moderation allows administrators to manage abuse and policy violations.
+
+---
+
+## Flag Content
+
+Marks content for review.
+
+Audit event:
+
+```text
+content_flagged
+```
+
+---
+
+## Disable Content
+
+Disabled content returns:
+
+```http
+410 Gone
+```
+
+Affected endpoints:
+
+```text
+/{slug}
+/p/{slug}
+/api/qr/{slug}.png
+/api/qr/{slug}.svg
+```
+
+Audit event:
+
+```text
+content_disabled
+```
+
+---
+
+## Enable Content
+
+Restores functionality.
+
+Audit event:
+
+```text
+content_enabled
+```
+
+---
+
+## Delete Content
+
+Permanently removes content.
+
+Audit event:
+
+```text
+content_deleted
+```
+
+---
+
+# Slug Management
+
+Route:
+
+```text
+/admin/slugs
+```
+
+Displays platform-wide slug ownership.
+
+Information includes:
+
+* Slug
+* Owner
+* Type
+* Status
+* Creation Date
+
+---
+
+## Slug Types
+
+Supported types:
+
+```text
+url
+page
+```
+
+---
+
+## Transfer Ownership
+
+Administrators may transfer ownership.
+
+Workflow:
+
+1. Validate recipient quota.
+2. Copy content.
+3. Update ownership.
+4. Update global slug registry.
+5. Write audit record.
+
+Audit event:
+
+```text
+slug_transfer
+```
+
+Analytics are preserved.
+
+---
+
+# Analytics
+
+Administrators can access analytics for any managed resource.
+
+---
+
+## URL Analytics
+
+Route:
+
+```text
+/admin/analytics/url/{id}
+```
+
+Displays:
+
+* Total Visits
+* Unique Visitors
+* Referrers
+* Browsers
+* Countries
+* Visit Timeline
+
+---
+
+## Page Analytics
+
+Route:
+
+```text
+/admin/analytics/page/{id}
+```
+
+Displays identical metrics for landing pages.
+
+---
+
+## User Analytics
+
+Administrators can review user-level analytics.
+
+Route:
+
+```text
+/analytics
+```
+
+Includes:
+
+* Top Links
+* Top Pages
+* Referrers
+* Browsers
+* Countries
+* Recent Visits
+
+---
+
+# Audit Logs
+
+Route:
+
+```text
+/admin/audit
+```
+
+All administrative actions are recorded.
+
+Searchable event types include:
+
+```text
+login
+logout
+failed_login
+user_created
+user_deleted
+user_disabled
+user_enabled
+password_reset
+quota_updated
+slug_transfer
+content_flagged
+content_disabled
+backup_created
+restore_executed
+```
+
+Audit logs should be reviewed regularly.
+
+---
+
+# Backup Management
+
+Route:
+
+```text
+/admin/backups
+```
+
+Provides web-based backup operations.
+
+---
+
+## Create Backup
+
+Creates a platform snapshot.
+
+Includes:
+
+```text
+users.db
+system.db
+tenant databases
+```
+
+Audit event:
+
+```text
+backup_created
+```
+
+---
+
+## Download Backup
+
+Allows local storage of backup archives.
+
+Recommended frequency:
+
+```text
+Daily
+```
+
+---
+
+## Restore Backup
+
+Restores a selected backup archive.
+
+Audit event:
+
+```text
+restore_executed
+```
+
+Always test restores before production use.
+
+---
+
+## Delete Backup
+
+Removes backup archives from storage.
+
+---
+
+# Health Dashboard
+
+Route:
+
+```text
+/admin/health
+```
+
+Provides operational diagnostics.
+
+Displays:
+
+* Database Status
+* WAL Status
+* Storage Utilization
+* Backup Status
+* Health Check Results
+* Quota Reconciliation Results
+
+---
+
+## Database Health
+
+Checks:
+
+```text
+users.db
+system.db
+content.db
+analytics.db
+```
+
+Reports:
+
+```text
+healthy
+warning
+error
+```
+
+---
+
+## Storage Monitoring
+
+Shows:
+
+* Total Storage
+* Free Storage
+* Database Sizes
+* Backup Sizes
+
+---
+
+# Security Administration
+
+## Password Policies
+
+Recommendations:
+
+* Minimum 12 characters
+* Unique passwords
+* Password manager usage
+
+---
+
+## Session Management
+
+Recommended actions:
+
+* Revoke old sessions
+* Review active sessions
+* Remove inactive users
+
+---
+
+## CSRF Protection
+
+All administrative forms require valid CSRF tokens.
+
+Invalid requests return:
+
+```http
+403 Forbidden
+```
+
+---
+
+## Audit Reviews
+
+Recommended review schedule:
+
+| Event Type        | Frequency |
+| ----------------- | --------- |
+| Failed Logins     | Daily     |
+| User Creation     | Weekly    |
+| Slug Transfers    | Weekly    |
+| Backup Events     | Daily     |
+| Moderation Events | Weekly    |
+
+---
+
+# Disaster Recovery
+
+Recommended workflow:
+
+1. Stop BZOD.
+2. Create backup copy.
+3. Restore archive.
+4. Verify databases.
+5. Run integrity checks.
+6. Restart service.
+
+---
+
+# Operational Best Practices
+
+Recommended:
+
+* Enable HTTPS
+* Run daily backups
+* Monitor disk usage
+* Review audit logs
+* Keep binaries updated
+* Test restore procedures regularly
+
+Avoid:
+
+* Manual database modifications
+* Direct deletion of tenant databases
+* Disabling audit logging
+
+---
+
+# Troubleshooting
+
+## User Cannot Login
+
+Check:
+
+* User status
+* Session validity
+* Password reset history
+
+---
+
+## Slug Already Exists
+
+Check:
+
+```text
+/admin/slugs
+```
+
+for ownership conflicts.
+
+---
+
+## Analytics Missing
+
+Verify:
+
+* Analytics worker running
+* Analytics database present
+* Event queue processing
+
+---
+
+## Backup Failure
+
+Check:
+
+* Free disk space
+* File permissions
+* Backup destination path
+
+---
+
+# Summary
+
+The BZOD administration system provides:
+
+* Centralized user management
+* Quotas and session controls
+* Moderation and slug ownership management
+* Analytics visibility
+* Audit logging
+* Backup and restore capabilities
+* Health monitoring
+
+while maintaining strong tenant isolation and a SQLite-native operational model.
+
+---
+
+End of Document.

docs/ARCHITECTURE.md

@@ -0,0 +1,650 @@
+# BZOD Architecture Guide
+
+Version: v0.5.0
+
+---
+
+# Overview
+
+BZOD is a self-hosted multi-user URL management platform written in Rust.
+
+The platform combines:
+
+* URL shortening
+* Landing pages
+* QR code generation
+* Analytics
+* User management
+* Moderation
+* Audit logging
+* Backup & restore
+* Disaster recovery
+
+into a single deployable binary powered entirely by SQLite.
+
+BZOD is designed around operational simplicity, tenant isolation, and long-term maintainability.
+
+---
+
+# Architectural Goals
+
+The primary design goals are:
+
+1. Self-hosted first
+2. SQLite-first architecture
+3. Multi-user operation
+4. Tenant isolation
+5. Simple deployment
+6. Minimal dependencies
+7. Easy backup and recovery
+8. No vendor lock-in
+
+---
+
+# High-Level Architecture
+
+```text
+                     ┌─────────────┐
+                     │   Browser   │
+                     └──────┬──────┘
+                            │
+                            ▼
+                 ┌────────────────────┐
+                 │     Axum Router    │
+                 └─────────┬──────────┘
+                           │
+      ┌────────────────────┼────────────────────┐
+      │                    │                    │
+      ▼                    ▼                    ▼
+
+  users.db           system.db         User Databases
+
+  Users              Global Slugs      content.db
+  Sessions           Audit Events      analytics.db
+  Quotas             Moderation
+  API Tokens         Settings
+```
+
+---
+
+# Runtime Components
+
+## Web Layer
+
+Location:
+
+```text
+src/web/
+```
+
+Responsible for:
+
+* HTTP routing
+* Dashboard rendering
+* Form handling
+* Authentication checks
+* Redirect handling
+* REST API endpoints
+
+Major modules:
+
+```text
+admin.rs
+api.rs
+pages.rs
+redirect.rs
+qr.rs
+system.rs
+multi_user.rs
+routes.rs
+```
+
+---
+
+## Authentication Layer
+
+Location:
+
+```text
+src/auth/
+```
+
+Responsible for:
+
+* Password hashing
+* Session validation
+* Cookie management
+* CSRF protection
+* Authorization
+
+Modules:
+
+```text
+csrf.rs
+middleware.rs
+password.rs
+session.rs
+```
+
+Authentication technologies:
+
+* Argon2id password hashing
+* Session cookies
+* CSRF tokens
+* RBAC checks
+
+---
+
+## Database Layer
+
+Location:
+
+```text
+src/db/
+```
+
+Responsible for:
+
+* Schema creation
+* Migrations
+* Database access
+* Analytics storage
+* User management
+
+Modules:
+
+```text
+admin.rs
+analytics.rs
+audit_events.rs
+content.rs
+migrations.rs
+sqlite.rs
+users.rs
+```
+
+---
+
+# Database Architecture
+
+BZOD uses multiple SQLite databases rather than a single monolithic database.
+
+This approach provides:
+
+* Better isolation
+* Easier backup
+* Simpler disaster recovery
+* Reduced risk of cross-user data leakage
+
+---
+
+## users.db
+
+Purpose:
+
+Central identity and account database.
+
+Contains:
+
+```text
+users
+sessions
+api_tokens
+quotas
+```
+
+Stores:
+
+* User accounts
+* Password hashes
+* Session records
+* API tokens
+* Quota information
+
+---
+
+## system.db
+
+Purpose:
+
+Global platform metadata.
+
+Contains:
+
+```text
+global_slugs
+audit_events
+moderation_events
+reserved_slugs
+settings
+slug_history
+```
+
+Stores:
+
+* Global slug ownership
+* Audit records
+* Moderation actions
+* Platform settings
+* Slug transfers
+
+---
+
+## Tenant Databases
+
+Each user receives isolated databases.
+
+Directory structure:
+
+```text
+users/
+└── <user_id>/
+    ├── content.db
+    └── analytics.db
+```
+
+---
+
+### content.db
+
+Stores:
+
+* URLs
+* Landing pages
+* Metadata
+
+---
+
+### analytics.db
+
+Stores:
+
+* Visits
+* Referrers
+* QR scans
+* Browser information
+* Analytics aggregates
+
+---
+
+# Multi-User Architecture
+
+BZOD v0.5.0 introduced complete tenant isolation.
+
+Each user owns:
+
+```text
+content.db
+analytics.db
+```
+
+Users cannot directly access:
+
+* Other users' URLs
+* Other users' landing pages
+* Other users' analytics
+
+The administrator accesses all tenants through controlled administrative interfaces.
+
+---
+
+# Global Slug Namespace
+
+All public URLs are tracked in:
+
+```text
+system.db -> global_slugs
+```
+
+Purpose:
+
+Prevent collisions across users.
+
+Example:
+
+```text
+User A owns:
+
+https://bzo.in/!office
+
+User B cannot create:
+
+https://bzo.in/!office
+```
+
+This guarantees global uniqueness.
+
+---
+
+# Request Lifecycle
+
+## URL Redirect
+
+Request:
+
+```text
+GET /abc123
+```
+
+Flow:
+
+```text
+Browser
+  ↓
+Axum Router
+  ↓
+global_slugs lookup
+  ↓
+Locate owner database
+  ↓
+Resolve URL
+  ↓
+Record analytics
+  ↓
+302 Redirect
+```
+
+---
+
+## Landing Page
+
+Request:
+
+```text
+GET /p/demo
+```
+
+Flow:
+
+```text
+Browser
+  ↓
+Router
+  ↓
+global_slugs lookup
+  ↓
+Tenant content.db lookup
+  ↓
+Render page
+```
+
+---
+
+## QR Generation
+
+Request:
+
+```text
+GET /api/qr/demo.svg
+```
+
+Flow:
+
+```text
+Router
+  ↓
+global_slugs lookup
+  ↓
+Generate QR
+  ↓
+Return SVG
+```
+
+---
+
+# Analytics Pipeline
+
+Location:
+
+```text
+src/analytics/
+```
+
+Components:
+
+```text
+events.rs
+queue.rs
+worker.rs
+aggregate.rs
+location.rs
+```
+
+Responsibilities:
+
+* Visit tracking
+* QR tracking
+* Browser detection
+* Referrer parsing
+* Aggregation
+
+---
+
+# Background Jobs
+
+Location:
+
+```text
+src/jobs/
+```
+
+Jobs:
+
+## aggregate.rs
+
+Analytics aggregation.
+
+## backup.rs
+
+Automated backups.
+
+## expiry.rs
+
+Expired content cleanup.
+
+## retention.rs
+
+Retention policy enforcement.
+
+## healthcheck.rs
+
+System health validation.
+
+## quota_reconcile.rs
+
+Quota consistency verification.
+
+---
+
+# Services Layer
+
+Location:
+
+```text
+src/services/
+```
+
+Purpose:
+
+Business logic abstraction.
+
+Modules:
+
+```text
+api_keys.rs
+audit.rs
+bulk.rs
+landing_pages.rs
+qr.rs
+shortener.rs
+```
+
+This layer separates business rules from HTTP handlers.
+
+---
+
+# CLI Architecture
+
+Location:
+
+```text
+src/cli/
+```
+
+The CLI and Web UI share the same internal services.
+
+Examples:
+
+```bash
+bzod create-admin
+bzod create-user
+bzod backup
+bzod restore
+bzod doctor
+bzod migrate
+```
+
+This avoids duplicate logic between administration methods.
+
+---
+
+# Security Model
+
+Security mechanisms:
+
+## Authentication
+
+* Argon2id password hashes
+* Session cookies
+
+## Authorization
+
+* RBAC
+* Administrative permission checks
+
+## CSRF Protection
+
+* Form tokens
+* Request validation
+
+## Tenant Isolation
+
+* Separate databases
+* Controlled access paths
+
+## Audit Logging
+
+All critical operations are recorded.
+
+Examples:
+
+* Login attempts
+* User creation
+* Password resets
+* Slug transfers
+* Moderation actions
+
+---
+
+# Backup & Recovery
+
+BZOD is designed for SQLite-first recovery.
+
+Backup targets:
+
+```text
+users.db
+system.db
+admin/
+users/*
+```
+
+Capabilities:
+
+* Full backups
+* Restore operations
+* Upgrade migrations
+* Disaster recovery validation
+
+---
+
+# Testing Architecture
+
+Location:
+
+```text
+tests/
+```
+
+Coverage includes:
+
+* Authentication
+* Authorization
+* User management
+* Analytics
+* Backups
+* Disaster recovery
+* Routing
+* Security
+* Concurrency
+* Upgrade validation
+* Multi-user isolation
+
+v0.5.0 includes more than 90 automated tests.
+
+---
+
+# Deployment Models
+
+Supported deployments:
+
+## Native
+
+```bash
+cargo build --release
+./bzod serve
+```
+
+## Systemd
+
+```text
+bzod.service
+```
+
+## Docker
+
+```text
+Dockerfile
+docker-compose.yml
+```
+
+---
+
+# Future Architecture Direction
+
+Planned for future releases:
+
+* Geo analytics
+* OpenAPI generation
+* SSO integration
+* Multi-organization support
+* Advanced reporting
+* Distributed analytics aggregation
+
+---
+
+# Summary
+
+BZOD v0.5.0 is built around a simple principle:
+
+> Keep deployment simple, keep data local, keep users isolated, and keep recovery easy.
+
+The platform achieves this through:
+
+* Rust
+* Axum
+* SQLite
+* Tenant isolation
+* Multi-database architecture
+* Strong automated validation
+* Operational simplicity

docs/BACKUP_RESTORE.md

@@ -0,0 +1,584 @@
+# Backup & Restore Guide
+
+Version: v0.5.0
+Applies To: BZOD Multi-User Platform
+
+---
+
+# Overview
+
+BZOD provides built-in backup and recovery functionality for both single-user and multi-user deployments.
+
+The backup architecture is designed to support:
+
+* Full platform backups
+* Individual tenant backups
+* Disaster recovery
+* Upgrade safety
+* Migration validation
+* Data integrity verification
+
+All production deployments should maintain regular backups before performing upgrades, maintenance, or administrative operations.
+
+---
+
+# Database Architecture
+
+BZOD stores data across multiple SQLite databases.
+
+## Core Databases
+
+```text
+data/
+├── users.db
+├── system.db
+└── users/
+```
+
+### users.db
+
+Stores:
+
+* User accounts
+* Password hashes
+* Account status
+* Roles
+* Sessions
+* Quotas
+* API tokens
+
+### system.db
+
+Stores:
+
+* Global slug registry
+* Reserved slugs
+* Slug ownership history
+* Audit events
+* Moderation events
+* System settings
+
+---
+
+## Tenant Databases
+
+Each tenant owns isolated content and analytics databases.
+
+```text
+data/users/{user_id}/
+├── content.db
+└── analytics.db
+```
+
+### content.db
+
+Stores:
+
+* Short URLs
+* Landing pages
+* Metadata
+* Tags
+* QR code configuration
+
+### analytics.db
+
+Stores:
+
+* Visit events
+* Referrers
+* Browser information
+* Country information
+* Aggregated statistics
+
+---
+
+# Backup Types
+
+## Full Platform Backup
+
+Creates a complete snapshot of the entire BZOD installation.
+
+Includes:
+
+```text
+users.db
+system.db
+all tenant content.db files
+all tenant analytics.db files
+```
+
+Recommended for:
+
+* Daily scheduled backups
+* Upgrades
+* Server migration
+* Disaster recovery
+
+---
+
+## User Backup
+
+Creates a backup of a single tenant.
+
+Includes:
+
+```text
+content.db
+analytics.db
+```
+
+Recommended for:
+
+* User export
+* User migration
+* User recovery
+
+---
+
+# CLI Backup Commands
+
+## Create Full Backup
+
+```bash
+bzod backup
+```
+
+Output:
+
+```text
+backups/
+└── backup-YYYYMMDD-HHMMSS.zip
+```
+
+---
+
+## Create User Backup
+
+```bash
+bzod backup-user 42
+```
+
+Output:
+
+```text
+backups/
+└── user-42-YYYYMMDD-HHMMSS.zip
+```
+
+---
+
+# CLI Restore Commands
+
+## Restore Full Backup
+
+```bash
+bzod restore backup-20260619-020000.zip
+```
+
+Restores:
+
+* users.db
+* system.db
+* all tenant databases
+
+---
+
+## Restore Single User
+
+```bash
+bzod restore-user user-42-20260619.zip
+```
+
+Restores only:
+
+```text
+users/42/content.db
+users/42/analytics.db
+```
+
+without affecting any other tenant.
+
+---
+
+# Web-Based Backup Management
+
+Administrative users can manage backups through:
+
+```text
+/admin/backups
+```
+
+Features:
+
+* Create backup
+* Download backup
+* Upload backup
+* Restore backup
+* Delete backup
+
+Only authenticated administrators may access backup operations.
+
+---
+
+# Backup Strategy
+
+## Recommended Schedule
+
+### Daily
+
+```text
+02:00 AM
+```
+
+Create a full platform backup.
+
+---
+
+### Weekly
+
+```text
+Sunday 03:00 AM
+```
+
+Create a full backup and copy it to:
+
+* NAS
+* Secondary server
+* External storage
+
+---
+
+### Monthly
+
+Archive a backup for long-term retention.
+
+Recommended retention:
+
+```text
+12 months
+```
+
+---
+
+# Retention Policy
+
+Recommended policy:
+
+```text
+Daily Backups:
+30 days
+
+Weekly Backups:
+12 weeks
+
+Monthly Backups:
+12 months
+```
+
+Adjust retention according to compliance requirements.
+
+---
+
+# Upgrade Procedure
+
+Always create a backup before upgrading.
+
+## Step 1
+
+Create backup:
+
+```bash
+bzod backup
+```
+
+## Step 2
+
+Upgrade BZOD binary.
+
+## Step 3
+
+Start BZOD.
+
+```bash
+bzod serve
+```
+
+## Step 4
+
+Allow database migrations to complete.
+
+## Step 5
+
+Verify:
+
+* Login
+* URLs
+* Landing pages
+* Analytics
+* Administration panels
+
+---
+
+# Restore Validation
+
+After every restore operation verify:
+
+## Authentication
+
+* Administrator login works
+* Standard user login works
+
+## Content
+
+* URLs are visible
+* Landing pages render correctly
+
+## Routing
+
+* Slug redirects work
+* Landing page routes resolve
+
+## Analytics
+
+* Visit counts exist
+* Analytics dashboards load
+
+## System
+
+* Audit events visible
+* Moderation records preserved
+* System settings preserved
+
+## Multi-User
+
+* Tenant isolation maintained
+* Ownership mappings preserved
+
+---
+
+# Disaster Recovery Scenarios
+
+## Scenario 1: Deleted User
+
+Problem:
+
+```text
+User account accidentally deleted.
+```
+
+Recovery:
+
+```bash
+bzod restore-user user-42.zip
+```
+
+Verify:
+
+* URLs restored
+* Pages restored
+* Analytics restored
+
+---
+
+## Scenario 2: Corrupted Tenant Database
+
+Problem:
+
+```text
+content.db corruption
+```
+
+Recovery:
+
+```bash
+bzod restore-user user-42.zip
+```
+
+or
+
+```bash
+bzod restore full-backup.zip
+```
+
+---
+
+## Scenario 3: Corrupted users.db
+
+Problem:
+
+```text
+Unable to login
+Missing users
+Session failures
+```
+
+Recovery:
+
+```bash
+bzod restore full-backup.zip
+```
+
+---
+
+## Scenario 4: Corrupted system.db
+
+Problem:
+
+```text
+Slug resolution failures
+Moderation data missing
+Settings lost
+```
+
+Recovery:
+
+```bash
+bzod restore full-backup.zip
+```
+
+---
+
+## Scenario 5: Complete Server Failure
+
+Problem:
+
+```text
+Disk failure
+Server loss
+Hardware replacement
+```
+
+Recovery:
+
+1. Reinstall operating system
+2. Install BZOD
+3. Restore backup
+
+```bash
+bzod restore backup.zip
+```
+
+4. Start BZOD
+
+```bash
+bzod serve
+```
+
+---
+
+# WAL Mode
+
+BZOD uses SQLite Write-Ahead Logging (WAL).
+
+Examples:
+
+```text
+users.db
+users.db-wal
+users.db-shm
+
+system.db
+system.db-wal
+system.db-shm
+
+content.db
+content.db-wal
+content.db-shm
+
+analytics.db
+analytics.db-wal
+analytics.db-shm
+```
+
+Benefits:
+
+* Improved concurrency
+* Better crash recovery
+* Faster write operations
+
+---
+
+# Backup Safety
+
+Do not manually copy live SQLite databases while the server is actively writing.
+
+Always use:
+
+```bash
+bzod backup
+```
+
+or the Backup Management UI.
+
+This ensures consistent snapshots.
+
+---
+
+# Security Considerations
+
+Backups may contain:
+
+* User accounts
+* Password hashes
+* Session metadata
+* Analytics data
+* Audit records
+* API token hashes
+
+Even though passwords and tokens are stored as hashes, backup archives should be treated as sensitive information.
+
+Recommended practices:
+
+* Encrypt backup storage
+* Restrict filesystem permissions
+* Maintain offsite copies
+* Transfer backups over secure channels
+* Test restores periodically
+
+---
+
+# Backup Testing
+
+A backup is only useful if it can be restored.
+
+Quarterly validation is recommended.
+
+Example:
+
+```bash
+mkdir restore-test
+
+bzod restore backup.zip \
+    --data-dir restore-test
+```
+
+Verify:
+
+* Login works
+* URLs resolve
+* Landing pages load
+* Analytics display
+* Administration dashboard functions
+
+---
+
+# Production Recommendation
+
+Minimum production policy:
+
+```text
+Daily Full Backup
+Weekly Offsite Backup
+Monthly Archive Backup
+Quarterly Restore Validation
+```
+
+Following this policy protects against:
+
+* User mistakes
+* Database corruption
+* Upgrade failures
+* Hardware failures
+* Site disasters
+
+and provides a reliable recovery path for BZOD deployments.

docs/CLI.md

@@ -0,0 +1,271 @@
+# BZOD Command Line Interface (CLI)
+
+BZOD includes a comprehensive command-line interface for server administration, backups, migrations, diagnostics, validation, and multi-user management.
+
+The current command list for BZOD v0.5.0 is:
+
+```text
+$ bzod --help
+
+BZOD - Personal Redirector & Landing Page Platform
+
+Usage: bzod <COMMAND>
+
+Commands:
+  serve           Start the BZOD web server
+  backup          Create a tar.gz backup of all databases
+  restore         Restore databases from a tar.gz backup file
+  migrate         Apply pending database schema migrations
+  stats           Print database statistics and record counts in the terminal
+  validate        Perform a one-shot validation of all registered short link destinations
+  create-admin    Create a new administrator user in the database
+  doctor          Run database diagnostics and health checks
+  shorten         Shorten a URL (Feature 3)
+  expand          Expand a shortened code or custom slug to its destination URL (Feature 4)
+  create-user     Create a new standard user in the database
+  delete-user     Delete a standard user and all their databases/slugs
+  disable-user    Disable a standard user
+  enable-user     Enable a standard user
+  reset-password  Reset standard user's password
+  list-users      List all standard/system users
+  backup-user     Backup a standard user's databases to a .tar.zst package
+  restore-user    Restore a standard user's databases from a .tar.zst package
+  help            Print this message or the help of the given subcommand(s)
+
+Options:
+  -h, --help  Print help
+```
+
+---
+
+# Server Operations
+
+## Start Web Server
+
+```bash
+bzod serve
+```
+
+---
+
+# Backup & Recovery
+
+## Full Backup
+
+```bash
+bzod backup
+```
+
+Creates a compressed backup archive containing:
+
+* users.db
+* system.db
+* content databases
+* analytics databases
+* user directories
+
+## Full Restore
+
+```bash
+bzod restore backup.tar.gz
+```
+
+Restores an entire BZOD installation from a backup archive.
+
+---
+
+# Database Operations
+
+## Apply Migrations
+
+```bash
+bzod migrate
+```
+
+Applies any pending database migrations.
+
+Safe to execute multiple times.
+
+## Database Statistics
+
+```bash
+bzod stats
+```
+
+Displays database statistics, record counts, storage usage, and operational metrics.
+
+---
+
+# Validation & Diagnostics
+
+## Validate Links
+
+```bash
+bzod validate
+```
+
+Checks all registered URLs and reports invalid destinations.
+
+## Health Diagnostics
+
+```bash
+bzod doctor
+```
+
+Performs:
+
+* SQLite integrity checks
+* WAL validation
+* Database availability checks
+* Storage verification
+* System health diagnostics
+
+---
+
+# URL Management
+
+## Create Short URL
+
+```bash
+bzod shorten https://example.com
+```
+
+## Expand Existing URL
+
+```bash
+bzod expand abc123
+```
+
+Returns the destination URL associated with the slug.
+
+---
+
+# Administrator Management
+
+## Create Administrator
+
+```bash
+bzod create-admin admin
+```
+
+Creates a new administrator account.
+
+---
+
+# User Management
+
+## List Users
+
+```bash
+bzod list-users
+```
+
+Displays all users in the platform.
+
+## Create User
+
+```bash
+bzod create-user alice
+```
+
+Creates a new standard user.
+
+## Disable User
+
+```bash
+bzod disable-user alice
+```
+
+Blocks login and invalidates sessions.
+
+## Enable User
+
+```bash
+bzod enable-user alice
+```
+
+Re-enables a disabled user.
+
+## Reset Password
+
+```bash
+bzod reset-password alice
+```
+
+Resets a user's password.
+
+## Delete User
+
+```bash
+bzod delete-user alice
+```
+
+Deletes:
+
+* User account
+* User databases
+* Sessions
+* API tokens
+* Slug ownership
+
+---
+
+# User Backup Operations
+
+## Backup User
+
+```bash
+bzod backup-user alice
+```
+
+Creates a portable `.tar.zst` archive containing all user-owned data.
+
+## Restore User
+
+```bash
+bzod restore-user alice.tar.zst
+```
+
+Restores a user from a previously generated archive.
+
+---
+
+# Recommended Maintenance
+
+Daily:
+
+```bash
+bzod doctor
+```
+
+Weekly:
+
+```bash
+bzod backup
+```
+
+Before Upgrades:
+
+```bash
+bzod backup
+bzod validate
+```
+
+After Upgrades:
+
+```bash
+bzod migrate
+bzod doctor
+```
+
+---
+
+# Related Documentation
+
+* INSTALL.md
+* MULTI_USER.md
+* ADMIN_GUIDE.md
+* BACKUP_RESTORE.md
+* SECURITY.md
+* API.md
+* ARCHITECTURE.md

docs/COMPARISON.md

@@ -1,382 +1,331 @@
-# BZOD vs Other Self-Hosted URL Shorteners
+# BZOD v0.5.0 vs Self-Hosted URL Management Platforms
 
-**BZOD (nx9-url-shortener)** is a modern, privacy-focused, self-hosted URL management platform built in Rust as part of the **NX9 Platform**.
+BZOD is a modern, privacy-focused, self-hosted URL Management Platform written in Rust and developed as part of the NX9 Platform.
 
-Unlike many traditional URL shorteners that focus solely on redirects, BZOD combines:
+Unlike traditional URL shorteners that focus primarily on URL redirection, BZOD provides a complete platform for managing URLs, landing pages, analytics, users, permissions, backups, and operational workflows.
+
+---
+
+# Executive Summary
+
+BZOD combines:
 
 * URL shortening
 * Landing pages
 * QR code generation
 * QR analytics
-* Password protection
+* Link analytics
+* Password-protected links
 * Link expiration
 * REST API
-* CLI automation
-* Backup & restore
+* Administrative dashboard
+* Multi-user operation
+* User management
+* User quotas
+* Session management
 * Audit logging
-
-into a single lightweight deployment.
-
-**Philosophy:** *One binary. One command. Full ownership.*
-
----
-
-## At a Glance
-
-* Rust-based
-* Single ~18 MB binary
-* Embedded SQLite
-* No external services required
-* Landing pages
-* QR generation & analytics
-* Password-protected links
-* REST API
-* CLI automation
+* Moderation
 * Backup & restore
-* Audit trail
-* MIT OR Apache-2.0 licensed
-* One-command deployment
+* Disaster recovery tooling
+
+into a single Rust binary deployment.
 
 ---
 
-## Quick Comparison
+# At a Glance
 
-| Feature               | BZOD              | Shlink   | YOURLS   | Chhoto URL |
-| --------------------- | ----------------- | -------- | -------- | ---------- |
-| Language              | Rust              | PHP      | PHP      | Rust       |
-| Single Binary         | ✅                 | ❌        | ❌        | ✅          |
-| Landing Pages         | ✅                 | ❌        | Plugin   | ❌          |
-| QR Code + Analytics   | ✅                 | Partial  | Plugin   | Partial    |
-| Password Protection   | ✅                 | Limited  | Plugin   | ❌          |
-| Backup & Restore      | ✅                 | External | External | ❌          |
-| Audit Trail           | ✅                 | Limited  | Plugin   | ❌          |
-| CLI Tools             | ✅                 | Limited  | Limited  | Limited    |
-| Dependencies          | None              | PHP + DB | PHP + DB | None       |
-| Deployment Complexity | Low               | Medium   | High     | Low        |
-| License               | MIT OR Apache-2.0 | MIT      | MIT      | MIT        |
-
----
-
-## Design Philosophy
-
-| Principle                  | BZOD              |
-| -------------------------- | ----------------- |
-| Self-hosted                | ✅                 |
-| Privacy-first              | ✅                 |
-| Open Source                | MIT OR Apache-2.0 |
-| Vendor Lock-in             | None              |
-| Telemetry                  | None              |
-| External Services Required | None              |
-| Database Server Required   | No (SQLite)       |
+| Feature              | BZOD              |
+| -------------------- | ----------------- |
+| Language             | Rust              |
+| License              | MIT OR Apache-2.0 |
+| Deployment           | Single Binary     |
 | Runtime Dependencies | None              |
-| Single Binary              | Yes (~18 MB)      |
-| Linux-first                | Yes               |
+| Database             | SQLite            |
+| Multi-User           | Yes               |
+| Landing Pages        | Yes               |
+| QR Codes             | Yes               |
+| Analytics            | Yes               |
+| REST API             | Yes               |
+| CLI Tools            | Yes               |
+| Backups              | Built-in          |
+| Audit Logs           | Built-in          |
+| RBAC                 | Built-in          |
 
 ---
 
-## The NX9 Philosophy
+# What Changed in v0.5.0
 
-BZOD is part of the **NX9 Platform**.
+BZOD v0.5.0 introduces a major architectural evolution.
 
-NX9 projects follow strict engineering principles:
+## New Platform Capabilities
 
-* Linux-native first
-* Rust-first
-* Single binary deployments
-* No NodeJS
-* No React
-* No Python runtime dependencies
-* No vendor lock-in
-* No telemetry
-* Privacy-first by default
-* MIT OR Apache-2.0 licensed
+* Multi-user architecture
+* Tenant isolation
+* Global slug namespace
+* User management
+* User quotas
+* Session management
+* Administrative dashboards
+* User self-service dashboards
+* Audit event logging
+* Moderation workflows
+* Backup management
+* Health monitoring
+* Upgrade framework
+* Migration tooling
 
-GitHub and Codeberg are source-code repositories, not the projects themselves.
+BZOD is no longer merely a URL shortener.
 
-The software is the project.
-
-The goal of NX9 is simple:
-
-> Build technology that serves people, organizations, communities, and governments — not advertising networks, data brokers, or vendor ecosystems.
+It is now a self-hosted URL Management Platform.
 
 ---
 
-## Why BZOD Exists
+# Traditional URL Shortener Comparison
 
-Most self-hosted URL shorteners optimize for one of two extremes:
-
-### 1. Minimal Redirect Service
-
-A tiny application that creates short links and redirects traffic.
-
-Advantages:
-
-* Extremely lightweight
-* Easy to understand
-* Easy to maintain
-
-Disadvantages:
-
-* Limited administration
-* Limited analytics
-* Limited security features
-* Often requires additional tools
-
-### 2. Large Multi-Service Platform
-
-Feature-rich systems with extensive integrations and dependencies.
-
-Advantages:
-
-* Powerful analytics
-* Advanced routing
-* Large ecosystems
-
-Disadvantages:
-
-* More infrastructure
-* More maintenance
-* Higher resource requirements
-
-### BZOD's Approach
-
-BZOD intentionally sits in the middle.
-
-It is:
-
-* Small enough for a Raspberry Pi
-* Powerful enough for organizations
-* Simple enough for homelabs
-* Complete enough for production use
+| Capability          | BZOD | Shlink   | YOURLS   | Chhoto URL |
+| ------------------- | ---- | -------- | -------- | ---------- |
+| URL Shortening      | ✅    | ✅        | ✅        | ✅          |
+| Landing Pages       | ✅    | ❌        | Plugin   | ❌          |
+| QR Generation       | ✅    | Partial  | Plugin   | Partial    |
+| QR Analytics        | ✅    | Partial  | Plugin   | ❌          |
+| Password Protection | ✅    | Limited  | Plugin   | ❌          |
+| Link Expiration     | ✅    | ✅        | Plugin   | Limited    |
+| REST API            | ✅    | ✅        | ✅        | JSON-RPC   |
+| Backup & Restore    | ✅    | External | External | ❌          |
+| Audit Logs          | ✅    | Limited  | Plugin   | ❌          |
+| Multi User          | ✅    | Partial  | Plugin   | ❌          |
+| User Quotas         | ✅    | ❌        | ❌        | ❌          |
+| User Isolation      | ✅    | ❌        | ❌        | ❌          |
+| User Dashboards     | ✅    | ❌        | ❌        | ❌          |
 
 ---
 
-# BZOD vs Go URL Shorteners
+# Multi-User Platform Comparison
 
-Popular Go projects include:
+BZOD v0.5.0 introduces first-class multi-user support.
+
+| Capability             | BZOD |
+| ---------------------- | ---- |
+| User Accounts          | ✅    |
+| Administrator Accounts | ✅    |
+| User Isolation         | ✅    |
+| User Quotas            | ✅    |
+| Session Management     | ✅    |
+| API Tokens             | ✅    |
+| Audit Trail            | ✅    |
+| Moderation             | ✅    |
+| Tenant Analytics       | ✅    |
+| Self-Service Portal    | ✅    |
+
+Most self-hosted URL shorteners are fundamentally single-user applications.
+
+BZOD is designed for:
+
+* Individuals
+* Teams
+* Organizations
+* Educational Institutions
+* Governments
+* Service Providers
+
+---
+
+# Security Comparison
+
+| Security Feature          | BZOD | Typical URL Shortener |
+| ------------------------- | ---- | --------------------- |
+| Argon2id Password Hashing | ✅    | Varies                |
+| Session Management        | ✅    | Basic                 |
+| CSRF Protection           | ✅    | Varies                |
+| RBAC                      | ✅    | Rare                  |
+| Audit Logging             | ✅    | Rare                  |
+| User Disablement          | ✅    | Rare                  |
+| Moderation Controls       | ✅    | Rare                  |
+| Tenant Isolation          | ✅    | Rare                  |
+| API Token Security        | ✅    | Varies                |
+
+---
+
+# Operations Comparison
+
+| Operational Feature | BZOD |
+| ------------------- | ---- |
+| Backup Creation     | ✅    |
+| Backup Restore      | ✅    |
+| User Backup         | ✅    |
+| User Restore        | ✅    |
+| Disaster Recovery   | ✅    |
+| Upgrade Validation  | ✅    |
+| Health Monitoring   | ✅    |
+| WAL Recovery        | ✅    |
+| Migration Framework | ✅    |
+
+Most competing products rely on external tooling for these capabilities.
+
+---
+
+# Deployment Comparison
+
+| Requirement                | BZOD | Shlink   | YOURLS   |
+| -------------------------- | ---- | -------- | -------- |
+| Single Binary              | ✅    | ❌        | ❌        |
+| SQLite Only                | ✅    | Optional | Optional |
+| External Database Required | ❌    | Usually  | Usually  |
+| Docker Support             | ✅    | ✅        | ✅        |
+| Systemd Support            | ✅    | Manual   | Manual   |
+| Backup Framework           | ✅    | ❌        | ❌        |
+| Upgrade Framework          | ✅    | ❌        | ❌        |
+
+---
+
+# BZOD vs Go-Based URL Shorteners
+
+Popular Go alternatives include:
 
 * Krtk
-* Slash
 * Goshorly
+* Slash
 * Shortr
 * Custom Gin/Echo implementations
 
-## Detailed Comparison
+### Strengths of Go Projects
 
-| Aspect              | BZOD (Rust)          | Typical Go Projects |
-| ------------------- | -------------------- | ------------------- |
-| Binary              | Single ~18 MB binary | Usually 10–20 MB    |
-| Runtime             | None                 | None                |
-| Database            | Embedded SQLite      | SQLite / PostgreSQL |
-| Landing Pages       | ✅ Built-in           | Rare                |
-| QR Generation       | ✅                    | Sometimes           |
-| QR Analytics        | ✅                    | Rare                |
-| Password Protection | ✅                    | Varies              |
-| Link Expiry         | ✅                    | Often               |
-| One-Time Links      | ✅                    | Rare                |
-| UTM Builder         | ✅                    | Rare                |
-| REST API            | ✅                    | Usually             |
-| CLI                 | ✅ Extensive          | Usually limited     |
-| Backup & Restore    | ✅ Built-in           | Rare                |
-| Audit Logs          | ✅                    | Rare                |
-| Admin Dashboard     | ✅                    | Varies              |
+* Small binaries
+* Excellent performance
+* Simple codebases
 
-### Summary
+### Strengths of BZOD
 
-Go shorteners are often:
-
-* Extremely simple
-* Fast
-* Easy to extend
-
-BZOD focuses on:
-
-* Rich built-in functionality
-* Complete ownership
-* Minimal operations
-* Batteries-included deployment
-
----
-
-# BZOD vs Python URL Shorteners
-
-Popular Python projects include:
-
-* Pygmy
-* ReducePy
-* Schort
-* Flask/FastAPI examples
-
-## Detailed Comparison
-
-| Aspect           | BZOD (Rust)           | Python Solutions  |
-| ---------------- | --------------------- | ----------------- |
-| Runtime          | None                  | Python required   |
-| Deploy Size      | ~18 MB                | Often 100+ MB     |
-| Memory Usage     | Very Low              | Moderate          |
-| Landing Pages    | ✅                     | Rare              |
-| QR Analytics     | ✅                     | Rare              |
-| Backup & Restore | ✅                     | Rare              |
-| CLI Tools        | ✅                     | Limited           |
-| Dashboard        | ✅                     | Varies            |
-| Security         | Argon2id + Audit Logs | Project dependent |
-| Performance      | Excellent             | Good              |
-
-### Summary
-
-Python solutions are ideal when:
-
-* Already using Python
-* Rapid prototyping
-* Easy customization
-
-BZOD is ideal when:
-
-* Long-term deployment matters
-* Resource efficiency matters
-* Minimal maintenance is desired
-
----
-
-# BZOD vs Shlink
-
-Shlink is one of the most mature self-hosted URL shorteners available.
-
-## Detailed Comparison
-
-| Aspect                   | BZOD          | Shlink           |
-| ------------------------ | ------------- | ---------------- |
-| Language                 | Rust          | PHP              |
-| Deployment               | Single binary | PHP stack        |
-| External DB              | No            | Usually yes      |
-| Landing Pages            | ✅             | ❌                |
-| Password Protected Links | ✅             | Limited          |
-| QR Analytics             | ✅             | Partial          |
-| UTM Builder              | ✅             | ❌                |
-| Backup & Restore         | ✅             | External tooling |
-| Audit Trail              | ✅             | Limited          |
-| Dynamic Redirect Rules   | ❌             | ✅                |
-| Multi-domain             | Planned       | ✅                |
-| Ecosystem                | Growing       | Mature           |
-
-### Summary
-
-Choose Shlink when:
-
-* Multi-domain management is critical
-* Dynamic redirect rules are required
-* Enterprise-scale analytics matter
-
-Choose BZOD when:
-
-* Simplicity matters
-* Privacy matters
-* Minimal infrastructure matters
-* Landing pages are important
-
----
-
-# BZOD vs YOURLS
-
-YOURLS is the classic self-hosted URL shortener.
-
-## Detailed Comparison
-
-| Aspect        | BZOD          | YOURLS     |
-| ------------- | ------------- | ---------- |
-| Language      | Rust          | PHP        |
-| Architecture  | Single binary | LAMP stack |
-| Plugins       | Not required  | Extensive  |
-| Landing Pages | ✅             | Plugin     |
-| QR Analytics  | ✅             | Plugin     |
-| Audit Logs    | ✅             | Plugin     |
-| Backup Tools  | ✅             | External   |
-| API           | ✅             | ✅          |
-| Maintenance   | Minimal       | Moderate   |
-
-### Summary
-
-YOURLS wins on:
-
-* Age
-* Community
-* Plugin ecosystem
-
-BZOD wins on:
-
-* Simplicity
-* Deployment
-* Modern architecture
-* Integrated features
-
----
-
-# BZOD vs Chhoto URL
-
-Chhoto URL is the closest Rust-based competitor.
-
-## Detailed Comparison
-
-| Aspect           | BZOD   | Chhoto URL |
-| ---------------- | ------ | ---------- |
-| Language         | Rust   | Rust       |
-| Landing Pages    | ✅      | ❌          |
-| QR Codes         | ✅      | ✅          |
-| QR Analytics     | ✅      | ❌          |
-| Password Links   | ✅      | ❌          |
-| Backup & Restore | ✅      | ❌          |
-| REST API         | ✅      | JSON-RPC   |
-| Audit Logs       | ✅      | ❌          |
-| Analytics        | Rich   | Basic      |
-| Binary Size      | ~18 MB | Smaller    |
-
-### Summary
-
-Choose Chhoto URL for:
-
-* Maximum simplicity
-* Minimal footprint
-
-Choose BZOD for:
-
-* Feature completeness
-* Better administration
-* Better analytics
-
----
-
-## Future Comparisons
-
-Additional comparison sections may be added in the future for:
-
-* Bitly
-* Dub
-* Pygmy
-* Krtk
-* Other self-hosted URL management platforms
-
----
-
-## Conclusion
-
-**BZOD is not merely a URL shortener.**
-
-It is a lightweight URL management platform that combines:
-
-* Link shortening
+* Multi-user support
 * Landing pages
-* QR services
+* User management
+* Built-in analytics
+* Backup framework
+* Audit logging
+* Moderation
+* Administrative dashboards
+
+---
+
+# BZOD vs Python-Based Solutions
+
+Examples:
+
+* Pygmy
+* Schort
+* ReducePy
+* Flask-based projects
+* FastAPI-based projects
+
+### Python Advantages
+
+* Rapid development
+* Familiar ecosystem
+
+### BZOD Advantages
+
+* No runtime dependency
+* Lower memory consumption
+* Single binary deployment
+* Operational tooling included
+* Better long-term maintenance characteristics
+
+---
+
+# Reliability & Testing
+
+BZOD v0.5.0 includes a comprehensive automated validation suite.
+
+Coverage includes:
+
+* Unit tests
+* Integration tests
+* HTTP E2E tests
+* Business workflow tests
+* Upgrade validation tests
+* Backup/restore tests
+* Disaster recovery tests
+* Security tests
+* Concurrency tests
+* WAL recovery tests
+
+The platform is validated using more than 90 automated tests.
+
+---
+
+# NX9 Platform Philosophy
+
+BZOD follows the NX9 engineering philosophy:
+
+* Linux-first
+* Rust-first
+* Self-hosted
+* Privacy-first
+* No telemetry
+* No vendor lock-in
+* No external dependencies
+* Single binary deployment
+
+The goal is simple:
+
+> Build software that remains useful, understandable, maintainable, and deployable decades into the future.
+
+---
+
+# Who Should Use BZOD?
+
+BZOD is suitable for:
+
+### Individuals
+
+* Personal URL management
+* Homelabs
+* Self-hosted services
+
+### Organizations
+
+* Marketing campaigns
+* Internal redirects
+* Landing page hosting
+
+### Governments
+
+* Public service redirects
+* Long-term link preservation
+* Controlled infrastructure
+
+### Service Providers
+
+* Multi-tenant URL management
+* Managed short-link services
+* White-label deployments
+
+---
+
+# Conclusion
+
+BZOD v0.5.0 is not simply a URL shortener.
+
+It is a self-hosted URL Management Platform providing:
+
+* Multi-user operation
+* Tenant isolation
+* URL shortening
+* Landing pages
+* QR generation
 * Analytics
-* Automation
-* Security
-* Backups
+* Audit logging
+* Moderation
+* User administration
+* Backup & restore
+* Health monitoring
 
-into a single deployable Rust binary.
+within a single Rust binary deployment.
 
-As part of the NX9 Platform, BZOD follows a simple principle:
+BZOD is designed for individuals, organizations, governments, educational institutions, and service providers that require full ownership of their links, analytics, and infrastructure.
 
-> Own your links. Own your data. Own your infrastructure.
+> Own your links.
+> Own your data.
+> Own your infrastructure.
 
 No telemetry. No vendor lock-in. No unnecessary complexity.
-
-For users seeking privacy, simplicity, ownership, and long-term sustainability, BZOD offers a compelling alternative to both cloud SaaS platforms and traditional self-hosted URL shorteners.

docs/DATABASES.md

@@ -0,0 +1,503 @@
+# DATABASES.md
+
+# BZOD Database Architecture
+
+BZOD v0.5.0 uses SQLite exclusively.
+
+Rather than using a single monolithic database, BZOD separates data into administrative and tenant-specific databases. This architecture improves security, isolation, backup flexibility, disaster recovery, and scalability.
+
+---
+
+# Overview
+
+BZOD stores data in the following structure:
+
+```text
+data/
+├── admin/
+│   ├── admin.db
+│   ├── system.db
+│   └── users.db
+│
+└── users/
+    ├── 1/
+    │   ├── analytics.db
+    │   ├── content.db
+    │   └── profile.db
+    │
+    ├── 2/
+    │   ├── analytics.db
+    │   ├── content.db
+    │   └── profile.db
+    │
+    └── N/
+        ├── analytics.db
+        ├── content.db
+        └── profile.db
+```
+
+Each user receives isolated databases.
+
+No user content or analytics are stored in the central administrative databases.
+
+---
+
+# Administrative Databases
+
+Administrative databases are located under:
+
+```text
+data/admin/
+```
+
+---
+
+# users.db
+
+Primary authentication and user management database.
+
+Purpose:
+
+* User accounts
+* Password hashes
+* Sessions
+* Quotas
+* API tokens
+* User status tracking
+
+Typical tables:
+
+```text
+users
+sessions
+quotas
+api_tokens
+```
+
+Responsibilities:
+
+* Authentication
+* Authorization
+* Session management
+* Account status
+* Quota enforcement
+
+This is the primary identity database of the platform.
+
+---
+
+# system.db
+
+Global platform database.
+
+Purpose:
+
+* Global slug namespace
+* Moderation
+* Auditing
+* System configuration
+
+Typical tables:
+
+```text
+global_slugs
+slug_history
+moderation_events
+audit_events
+reserved_slugs
+settings
+```
+
+Responsibilities:
+
+* Global slug uniqueness
+* Slug ownership
+* Moderation actions
+* Audit logging
+* System settings
+
+Every redirect ultimately resolves through records stored in this database.
+
+---
+
+# admin.db
+
+Administrative application database.
+
+Purpose:
+
+* Administrative metadata
+* Administrative API key records
+* Legacy compatibility structures
+* Internal management data
+
+Typical tables:
+
+```text
+api_keys
+audit_events
+```
+
+This database is reserved for administrative functions and does not store tenant content.
+
+---
+
+# Tenant Databases
+
+Tenant databases are located under:
+
+```text
+data/users/{user_id}/
+```
+
+Each user owns a completely isolated set of databases.
+
+Example:
+
+```text
+data/users/2/
+├── analytics.db
+├── content.db
+└── profile.db
+```
+
+---
+
+# content.db
+
+Stores user-owned content.
+
+Purpose:
+
+* Short URLs
+* Landing pages
+* QR metadata
+* Preview metadata
+
+Typical tables:
+
+```text
+urls
+pages
+qr_codes
+previews
+```
+
+Responsibilities:
+
+* URL management
+* Landing page management
+* Content ownership
+
+This database contains the actual resources owned by a user.
+
+---
+
+# analytics.db
+
+Stores traffic and visitor information.
+
+Purpose:
+
+* Visit recording
+* Referrer tracking
+* Browser tracking
+* Country statistics
+* Aggregated analytics
+
+Typical tables:
+
+```text
+visits
+referrers
+browsers
+countries
+daily_stats
+```
+
+Responsibilities:
+
+* Analytics collection
+* Reporting
+* Dashboard statistics
+
+Analytics are fully isolated per user.
+
+Administrators access aggregated analytics by querying each user's analytics database.
+
+---
+
+# profile.db
+
+Stores user-specific profile information.
+
+Purpose:
+
+* User preferences
+* Profile settings
+* Future extensible metadata
+
+Typical tables:
+
+```text
+profile
+preferences
+```
+
+Responsibilities:
+
+* User profile management
+* Dashboard preferences
+* Future personalization features
+
+---
+
+# Database Isolation Model
+
+BZOD follows a strict tenant isolation model.
+
+```text
+User A
+ ├── content.db
+ ├── analytics.db
+ └── profile.db
+
+User B
+ ├── content.db
+ ├── analytics.db
+ └── profile.db
+```
+
+User databases never share tables.
+
+Cross-user content access is prevented by design.
+
+Benefits:
+
+* Security
+* Easier backups
+* Easier deletion
+* Reduced corruption impact
+
+---
+
+# Global Slug Registry
+
+The system maintains a single namespace.
+
+Stored in:
+
+```text
+system.db
+```
+
+Table:
+
+```text
+global_slugs
+```
+
+Example:
+
+```text
+abc123 → User 2 URL
+docs → User 5 Page
+demo → User 1 URL
+```
+
+This guarantees:
+
+* Global uniqueness
+* Ownership tracking
+* Moderation support
+* Slug transfer support
+
+---
+
+# Write Flow
+
+Creating a URL:
+
+```text
+1. Validate quota
+2. Register slug in system.db
+3. Create URL in content.db
+4. Update quota counters
+5. Write audit event
+```
+
+Creating a landing page:
+
+```text
+1. Validate quota
+2. Register slug in system.db
+3. Create page in content.db
+4. Update quota counters
+5. Write audit event
+```
+
+---
+
+# Analytics Flow
+
+Visitor request:
+
+```text
+GET /abc123
+```
+
+Process:
+
+```text
+global_slugs
+        ↓
+content.db lookup
+        ↓
+redirect
+        ↓
+analytics.db visit record
+```
+
+Analytics writes never modify content records.
+
+---
+
+# WAL Mode
+
+All databases operate in SQLite WAL mode.
+
+Verify:
+
+```sql
+PRAGMA journal_mode;
+```
+
+Expected:
+
+```text
+wal
+```
+
+Benefits:
+
+* Improved concurrency
+* Reduced write contention
+* Crash recovery
+
+Associated files:
+
+```text
+*.db
+*.db-shm
+*.db-wal
+```
+
+---
+
+# WAL Checkpointing
+
+Large WAL files are normal during heavy traffic.
+
+Example:
+
+```text
+analytics.db-wal
+content.db-wal
+```
+
+To manually checkpoint:
+
+```sql
+PRAGMA wal_checkpoint(TRUNCATE);
+```
+
+The healthcheck and backup jobs may trigger checkpoints automatically.
+
+---
+
+# Backups
+
+Recommended:
+
+```bash
+bzod backup
+```
+
+This creates a consistent archive of:
+
+```text
+admin/
+users/
+```
+
+Never manually copy live databases while the application is running.
+
+---
+
+# Integrity Verification
+
+Run:
+
+```bash
+bzod doctor
+```
+
+Or:
+
+```sql
+PRAGMA integrity_check;
+```
+
+Expected:
+
+```text
+ok
+```
+
+---
+
+# Migration System
+
+BZOD maintains schema versions using:
+
+```sql
+PRAGMA user_version;
+```
+
+Startup automatically executes:
+
+```text
+Db::init()
+```
+
+which:
+
+1. Creates missing databases
+2. Applies migrations
+3. Validates schemas
+4. Repairs legacy installations when required
+
+---
+
+# Design Principles
+
+BZOD database architecture prioritizes:
+
+* SQLite-only deployment
+* Multi-user isolation
+* Operational simplicity
+* Backup friendliness
+* Easy disaster recovery
+* Minimal dependencies
+* Single-binary deployment
+
+---
+
+# Related Documentation
+
+* ARCHITECTURE.md
+* MULTI_USER.md
+* BACKUP_RESTORE.md
+* INSTALL.md
+* UPGRADE.md
+* SECURITY.md

docs/INSTALL.md

@@ -0,0 +1,604 @@
+# BZOD Installation Guide
+
+Version: v0.5.0
+
+---
+
+# Introduction
+
+BZOD is a self-hosted multi-user URL management platform written in Rust.
+
+Features include:
+
+* URL shortening
+* Landing pages
+* QR code generation
+* Analytics
+* User management
+* Audit logging
+* Moderation
+* Backup & restore
+* Disaster recovery
+
+BZOD is distributed as a single executable and uses SQLite databases for storage.
+
+No PostgreSQL, MySQL, Redis, Elasticsearch, or external services are required.
+
+---
+
+# Installation Methods
+
+BZOD supports three deployment methods:
+
+| Method         | Recommended For  |
+| -------------- | ---------------- |
+| Docker Compose | Most deployments |
+| Native Binary  | Linux servers    |
+| Source Build   | Development      |
+
+---
+
+# System Requirements
+
+## Minimum
+
+| Component | Requirement  |
+| --------- | ------------ |
+| CPU       | 1 Core       |
+| Memory    | 512 MB       |
+| Storage   | 1 GB         |
+| OS        | Linux x86_64 |
+
+## Recommended
+
+| Component | Requirement              |
+| --------- | ------------------------ |
+| CPU       | 2+ Cores                 |
+| Memory    | 2 GB                     |
+| Storage   | 10+ GB SSD               |
+| OS        | Debian 12 / Ubuntu 24.04 |
+
+## Tested Platforms
+
+* Debian 12 Bookworm
+* Ubuntu 22.04
+* Ubuntu 24.04
+* Arch Linux
+* Docker
+* CasaOS
+
+---
+
+# Installation Using Docker
+
+## Prerequisites
+
+Install:
+
+```bash
+docker
+docker compose
+```
+
+Verify:
+
+```bash
+docker --version
+docker compose version
+```
+
+---
+
+## Create Directory
+
+```bash
+mkdir -p /opt/bzod
+cd /opt/bzod
+```
+
+---
+
+## Copy Files
+
+Required:
+
+```text
+docker-compose.yml
+Dockerfile
+```
+
+Optional:
+
+```text
+bzod.service
+```
+
+---
+
+## Start Container
+
+```bash
+docker compose up -d
+```
+
+Verify:
+
+```bash
+docker compose ps
+```
+
+View logs:
+
+```bash
+docker compose logs -f
+```
+
+---
+
+## Stop Container
+
+```bash
+docker compose down
+```
+
+---
+
+## Restart Container
+
+```bash
+docker compose restart
+```
+
+---
+
+# Native Installation
+
+## Install Dependencies
+
+### Debian / Ubuntu
+
+```bash
+sudo apt update
+
+sudo apt install -y \
+    build-essential \
+    pkg-config \
+    libssl-dev \
+    sqlite3
+```
+
+### Arch Linux
+
+```bash
+sudo pacman -S \
+    base-devel \
+    openssl \
+    sqlite
+```
+
+---
+
+## Download Release Binary
+
+Example:
+
+```bash
+wget https://example.com/bzod-v0.5.0-linux-amd64.tar.gz
+```
+
+Extract:
+
+```bash
+tar -xzf bzod-v0.5.0-linux-amd64.tar.gz
+```
+
+Install:
+
+```bash
+sudo install -m755 bzod /usr/local/bin/bzod
+```
+
+Verify:
+
+```bash
+bzod --help
+```
+
+---
+
+# Build From Source
+
+## Install Rust
+
+```bash
+curl https://sh.rustup.rs -sSf | sh
+```
+
+Verify:
+
+```bash
+cargo --version
+rustc --version
+```
+
+---
+
+## Clone Repository
+
+```bash
+git clone https://github.com/thakares/nx9-url-shortener.git
+
+cd nx9-url-shortener
+```
+
+---
+
+## Build
+
+Development:
+
+```bash
+cargo build
+```
+
+Release:
+
+```bash
+cargo build --release
+```
+
+Binary:
+
+```bash
+target/release/bzod
+```
+
+---
+
+# Data Directory
+
+BZOD automatically creates its databases on first startup.
+
+Default structure:
+
+```text
+data/
+├── users.db
+├── system.db
+│
+├── admin/
+│   ├── content.db
+│   └── analytics.db
+│
+└── users/
+    └── ...
+```
+
+Do not manually modify database files while BZOD is running.
+
+---
+
+# First Startup
+
+Run:
+
+```bash
+bzod serve
+```
+
+By default:
+
+```text
+http://localhost:8080
+```
+
+Open:
+
+```text
+http://localhost:8080
+```
+
+---
+
+# Bootstrap Administrator
+
+On a fresh installation:
+
+1. Open Login page
+2. Use bootstrap credentials
+3. Create the first administrator account
+4. Save the credentials securely
+
+After bootstrap:
+
+* Bootstrap mode is disabled
+* Normal authentication is enforced
+
+---
+
+# Create Administrator Using CLI
+
+Alternative method:
+
+```bash
+bzod create-admin
+```
+
+Follow prompts:
+
+```text
+Username:
+Password:
+```
+
+The administrator account is stored in:
+
+```text
+users.db
+```
+
+---
+
+# Reverse Proxy Configuration
+
+Using Nginx is recommended.
+
+Example:
+
+```nginx
+server {
+    server_name bzod.example.com;
+
+    location / {
+        proxy_pass http://127.0.0.1:8080;
+
+        proxy_set_header Host $host;
+        proxy_set_header X-Real-IP $remote_addr;
+
+        proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+
+        proxy_set_header X-Forwarded-Proto $scheme;
+    }
+}
+```
+
+Reload:
+
+```bash
+sudo nginx -t
+sudo systemctl reload nginx
+```
+
+---
+
+# HTTPS
+
+Recommended options:
+
+* Let's Encrypt
+* Nginx Proxy Manager
+* Caddy
+* Traefik
+
+Always use HTTPS in production.
+
+---
+
+# Running as Systemd Service
+
+Install binary:
+
+```bash
+sudo install -m755 bzod /usr/local/bin/bzod
+```
+
+Copy service:
+
+```bash
+sudo cp bzod.service /etc/systemd/system/
+```
+
+Reload:
+
+```bash
+sudo systemctl daemon-reload
+```
+
+Enable:
+
+```bash
+sudo systemctl enable bzod
+```
+
+Start:
+
+```bash
+sudo systemctl start bzod
+```
+
+Status:
+
+```bash
+sudo systemctl status bzod
+```
+
+Logs:
+
+```bash
+journalctl -u bzod -f
+```
+
+---
+
+# Firewall
+
+Open HTTP:
+
+```bash
+sudo ufw allow 8080/tcp
+```
+
+HTTPS:
+
+```bash
+sudo ufw allow 443/tcp
+```
+
+HTTP:
+
+```bash
+sudo ufw allow 80/tcp
+```
+
+---
+
+# Health Verification
+
+Open:
+
+```text
+http://localhost:8080
+```
+
+Login as administrator.
+
+Verify:
+
+* Dashboard loads
+* User list loads
+* URL creation works
+* Landing pages work
+* QR generation works
+* Analytics record visits
+
+---
+
+# Upgrade Procedure
+
+Always backup before upgrading.
+
+Create backup:
+
+```bash
+bzod backup
+```
+
+Stop service:
+
+```bash
+sudo systemctl stop bzod
+```
+
+Replace binary.
+
+Run migrations:
+
+```bash
+bzod migrate
+```
+
+Start service:
+
+```bash
+sudo systemctl start bzod
+```
+
+Verify logs.
+
+See:
+
+```text
+docs/UPGRADE.md
+```
+
+---
+
+# Troubleshooting
+
+## Port Already In Use
+
+Check:
+
+```bash
+ss -tulpn | grep 8080
+```
+
+Change port or stop conflicting service.
+
+---
+
+## Database Locked
+
+Verify only one BZOD instance is running:
+
+```bash
+ps aux | grep bzod
+```
+
+---
+
+## Permission Errors
+
+Verify ownership:
+
+```bash
+chown -R bzod:bzod data/
+```
+
+---
+
+## Login Problems
+
+Verify:
+
+* Administrator account exists
+* Session cookies enabled
+* System clock is correct
+
+---
+
+## View Logs
+
+Systemd:
+
+```bash
+journalctl -u bzod -f
+```
+
+Docker:
+
+```bash
+docker compose logs -f
+```
+
+---
+
+# Next Steps
+
+After installation:
+
+1. Read `MULTI_USER.md`
+2. Read `ADMIN_GUIDE.md`
+3. Configure backups
+4. Configure HTTPS
+5. Create additional users
+6. Verify restore procedures
+
+---
+
+# Additional Documentation
+
+| File              | Purpose                  |
+| ----------------- | ------------------------ |
+| ARCHITECTURE.md   | System architecture      |
+| MULTI_USER.md     | Multi-user design        |
+| ADMIN_GUIDE.md    | Administrative workflows |
+| BACKUP_RESTORE.md | Backup procedures        |
+| SECURITY.md       | Security model           |
+| CLI.md            | Command reference        |
+| API.md            | REST API reference       |
+| UPGRADE.md        | Upgrade instructions     |
+
+---
+
+End of Document.

docs/MULTI_USER.md

@@ -0,0 +1,732 @@
+# BZOD Multi-User Architecture Guide
+
+Version: v0.5.0
+
+---
+
+# Introduction
+
+BZOD v0.5.0 introduces a complete multi-user architecture that transforms BZOD from a single-tenant URL shortener into a secure, isolated, self-hosted multi-user platform.
+
+Each user receives logically isolated content and analytics storage while sharing a common authentication, administration, moderation, and routing infrastructure.
+
+This document explains the architecture, database layout, ownership model, security boundaries, quotas, slug management, and administrative workflows.
+
+---
+
+# Design Goals
+
+The multi-user architecture was designed around the following principles:
+
+* Strong tenant isolation
+* Single binary deployment
+* SQLite-only operation
+* Minimal operational complexity
+* No external services required
+* Global slug namespace
+* Centralized administration
+* Disaster recovery support
+* Simple backup and restore workflows
+
+---
+
+# User Types
+
+BZOD supports the following account types.
+
+## Administrator
+
+Administrators can:
+
+* Access the administrative dashboard
+* Create users
+* Delete users
+* Reset passwords
+* Manage quotas
+* Transfer ownership
+* Moderate content
+* Manage backups
+* Access health dashboards
+* Access audit logs
+
+Administrators cannot bypass database isolation.
+
+---
+
+## Standard User
+
+Standard users can:
+
+* Create short URLs
+* Create landing pages
+* View analytics
+* Generate QR codes
+* Manage API tokens
+* Update passwords
+
+Standard users cannot:
+
+* Access other user content
+* Access administrative functions
+* Access system settings
+
+---
+
+## System Accounts
+
+System accounts are reserved for internal operations.
+
+They cannot authenticate into the dashboard.
+
+---
+
+# Database Architecture
+
+BZOD uses multiple SQLite databases.
+
+## users.db
+
+Central identity store.
+
+Contains:
+
+```text
+users
+sessions
+quotas
+api_tokens
+```
+
+Responsibilities:
+
+* Authentication
+* Session management
+* Password verification
+* User status management
+* Quota tracking
+
+---
+
+## system.db
+
+Global platform database.
+
+Contains:
+
+```text
+global_slugs
+slug_history
+moderation_events
+audit_events
+settings
+reserved_slugs
+```
+
+Responsibilities:
+
+* Slug ownership
+* Moderation
+* Audit logging
+* Global settings
+* System metadata
+
+---
+
+## Tenant Databases
+
+Every tenant owns independent databases.
+
+Example:
+
+```text
+users/
+└── 15/
+    ├── content.db
+    └── analytics.db
+```
+
+Responsibilities:
+
+### content.db
+
+Stores:
+
+```text
+urls
+pages
+qr_metadata
+previews
+```
+
+### analytics.db
+
+Stores:
+
+```text
+visits
+aggregates
+referrers
+browsers
+countries
+```
+
+---
+
+# Directory Structure
+
+Example installation:
+
+```text
+data/
+├── users.db
+├── system.db
+│
+├── admin/
+│   ├── content.db
+│   └── analytics.db
+│
+└── users/
+    ├── 2/
+    │   ├── content.db
+    │   └── analytics.db
+    │
+    ├── 3/
+    │   ├── content.db
+    │   └── analytics.db
+    │
+    └── 4/
+        ├── content.db
+        └── analytics.db
+```
+
+---
+
+# Global Slug Namespace
+
+BZOD uses a platform-wide namespace.
+
+A slug can only exist once.
+
+Examples:
+
+```text
+/company
+/about
+/docs
+```
+
+If User A owns:
+
+```text
+/company
+```
+
+User B cannot create:
+
+```text
+/company
+```
+
+The operation is rejected.
+
+---
+
+# Slug Registration Flow
+
+When a URL or page is created:
+
+1. Validate quota.
+2. Validate slug.
+3. Register slug in system.db.
+4. Create record in tenant content.db.
+5. Increment quota counters.
+6. Write audit log.
+
+If any step fails:
+
+* Changes are rolled back.
+* Partial records are removed.
+
+---
+
+# Global Slug Table
+
+Conceptually:
+
+```text
+global_slugs
+```
+
+Contains:
+
+```text
+slug
+owner_user_id
+target_type
+target_id
+status
+created_at
+```
+
+Example:
+
+| slug | owner | type |
+| ---- | ----- | ---- |
+| docs | 3     | page |
+| api  | 8     | page |
+| home | 2     | url  |
+
+---
+
+# Slug Ownership Transfer
+
+Administrators may transfer ownership.
+
+Process:
+
+1. Validate destination quotas.
+2. Copy content.
+3. Move ownership.
+4. Update global slug registry.
+5. Record history.
+6. Write audit event.
+
+Analytics remain preserved.
+
+URLs remain functional.
+
+---
+
+# Tenant Isolation
+
+Each user owns independent databases.
+
+Example:
+
+```text
+User A
+└── users/2/
+
+User B
+└── users/3/
+```
+
+User A never accesses:
+
+```text
+users/3/content.db
+users/3/analytics.db
+```
+
+User B never accesses:
+
+```text
+users/2/content.db
+users/2/analytics.db
+```
+
+All access is enforced by application logic.
+
+---
+
+# Authentication Architecture
+
+Authentication is centralized.
+
+Stored in:
+
+```text
+users.db
+```
+
+Tables:
+
+```text
+users
+sessions
+```
+
+All dashboard sessions use:
+
+```text
+bzod_session
+```
+
+Sessions are validated against:
+
+```text
+users.db.sessions
+```
+
+---
+
+# Session Lifecycle
+
+Login:
+
+```text
+User Login
+    ↓
+Create Session
+    ↓
+Store in users.db
+    ↓
+Set bzod_session cookie
+```
+
+Logout:
+
+```text
+Delete session row
+    ↓
+Expire cookie
+```
+
+Disabled users immediately lose access.
+
+---
+
+# Quota System
+
+Every user has quotas.
+
+Examples:
+
+```text
+max_urls
+max_pages
+max_storage_mb
+max_api_tokens
+```
+
+Current utilization is tracked separately.
+
+Administrators may:
+
+* Increase limits
+* Reduce limits
+* Trigger reconciliation
+
+---
+
+# Quota Reconciliation
+
+Background job:
+
+```text
+quota_reconcile
+```
+
+Purpose:
+
+* Detect drift
+* Recount resources
+* Repair counters
+
+Example:
+
+```text
+Stored URLs = 50
+Actual URLs = 47
+```
+
+Counter automatically corrected.
+
+---
+
+# Analytics Isolation
+
+Each tenant stores analytics independently.
+
+Example:
+
+```text
+users/10/analytics.db
+```
+
+Contains only User 10 traffic.
+
+Administrators can:
+
+* View aggregated analytics
+* Access user analytics
+
+Users cannot view analytics from other tenants.
+
+---
+
+# QR Code System
+
+QR codes are generated dynamically.
+
+Endpoints:
+
+```text
+/api/qr/{slug}.png
+/api/qr/{slug}.svg
+```
+
+Slug ownership is resolved through:
+
+```text
+system.db.global_slugs
+```
+
+No content database scan is required.
+
+---
+
+# Moderation Architecture
+
+Administrators can:
+
+* Flag content
+* Disable content
+* Delete content
+* Transfer ownership
+
+Disabled content returns:
+
+```http
+410 Gone
+```
+
+For:
+
+```text
+/slug
+/p/slug
+/api/qr/slug.png
+/api/qr/slug.svg
+```
+
+---
+
+# Audit Logging
+
+All administrative actions are recorded.
+
+Examples:
+
+```text
+login
+logout
+user_create
+user_delete
+password_reset
+quota_update
+slug_transfer
+backup_create
+restore_execute
+```
+
+Stored in:
+
+```text
+system.db
+```
+
+---
+
+# Backup Architecture
+
+Supported levels:
+
+## Full Platform Backup
+
+Includes:
+
+```text
+users.db
+system.db
+all tenant databases
+```
+
+---
+
+## User Backup
+
+Includes:
+
+```text
+content.db
+analytics.db
+```
+
+For a specific user.
+
+---
+
+# Disaster Recovery
+
+Supported operations:
+
+```bash
+bzod backup
+bzod restore
+bzod backup-user
+bzod restore-user
+```
+
+Recovery preserves:
+
+* URLs
+* Pages
+* Analytics
+* Users
+* Slugs
+* Settings
+
+---
+
+# Upgrade Path
+
+BZOD automatically migrates:
+
+```text
+v0.4.x
+```
+
+to
+
+```text
+v0.5.x
+```
+
+Migration process:
+
+1. Create users.db.
+2. Create system.db.
+3. Create admin tenant.
+4. Migrate content.
+5. Migrate analytics.
+6. Populate global_slugs.
+7. Create legacy_admin.
+8. Validate integrity.
+
+No manual database migration is normally required.
+
+---
+
+# Security Model
+
+Security boundaries:
+
+## Authentication
+
+Centralized.
+
+```text
+users.db
+```
+
+---
+
+## Authorization
+
+Role-based.
+
+```text
+admin
+standard
+system
+```
+
+---
+
+## CSRF Protection
+
+All forms protected.
+
+Invalid tokens:
+
+```http
+403 Forbidden
+```
+
+---
+
+## Session Security
+
+* Secure session IDs
+* Session invalidation
+* Expiration support
+* Replay protection
+
+---
+
+## Tenant Isolation
+
+Per-user databases.
+
+No shared content tables.
+
+---
+
+# Operational Recommendations
+
+Recommended deployment:
+
+```text
+Nginx
+    ↓
+BZOD
+    ↓
+SQLite WAL
+```
+
+Enable:
+
+* HTTPS
+* Daily backups
+* Log rotation
+* Health monitoring
+
+---
+
+# Limitations
+
+Current v0.5.0 limitations:
+
+* SQLite backend only
+* Single server deployment
+* No clustering
+* No federation
+* No organization account hierarchy
+
+These may be addressed in future releases.
+
+---
+
+# Future Expansion
+
+Potential v0.6.x features:
+
+* Organization accounts
+* Service accounts
+* SSO integration
+* Multi-node replication
+* Advanced analytics dashboards
+* Scheduled tasks UI
+
+---
+
+# Summary
+
+BZOD v0.5.0 provides:
+
+* Centralized authentication
+* Multi-user isolation
+* Global slug namespace
+* Per-user analytics
+* Administrative moderation
+* Quotas
+* Audit logging
+* Backup & disaster recovery
+* Single-binary deployment
+
+while remaining lightweight, SQLite-native, and operationally simple.
+
+---
+
+End of Document.

docs/SECURITY.md

@@ -0,0 +1,662 @@
+# BZOD Security Guide
+
+Version: v0.5.0
+
+---
+
+# Security Overview
+
+BZOD is designed as a self-hosted URL shortener and landing page platform with a strong emphasis on:
+
+* Multi-user isolation
+* Secure authentication
+* Role-based access control
+* Auditability
+* Data ownership
+* Disaster recovery
+* Operational simplicity
+
+This document describes the security architecture, threat model, authentication mechanisms, authorization controls, and operational security recommendations for BZOD v0.5.0.
+
+---
+
+# Security Principles
+
+BZOD follows several core principles:
+
+1. Least Privilege
+2. Tenant Isolation
+3. Defense in Depth
+4. Auditability
+5. Secure Defaults
+6. Explicit Ownership
+7. Fail Secure
+
+---
+
+# Threat Model
+
+BZOD is designed to protect against:
+
+* Unauthorized dashboard access
+* Credential theft
+* Session hijacking
+* Cross-user data access
+* Slug takeover attempts
+* Privilege escalation
+* CSRF attacks
+* XSS injection attempts
+* Unauthorized API access
+* Malicious content modification
+* Accidental administrative mistakes
+
+BZOD is not intended to defend against:
+
+* Physical server compromise
+* Root-level operating system compromise
+* Malware running as the BZOD service user
+* Full database theft by a privileged host administrator
+
+---
+
+# Authentication
+
+Authentication is centralized in:
+
+```text
+users.db
+```
+
+Tables:
+
+```text
+users
+sessions
+api_tokens
+```
+
+All users authenticate through the same identity system.
+
+---
+
+# Password Security
+
+Passwords are never stored in plaintext.
+
+Stored values:
+
+```text
+password_hash
+```
+
+Passwords are hashed before storage.
+
+Administrative password resets generate entirely new hashes.
+
+Existing passwords cannot be recovered.
+
+---
+
+# Session Security
+
+All dashboard authentication uses:
+
+```text
+bzod_session
+```
+
+cookie.
+
+Sessions are stored in:
+
+```text
+users.db.sessions
+```
+
+Each session contains:
+
+```text
+session_id
+user_id
+created_at
+expires_at
+```
+
+---
+
+## Session Validation
+
+Each authenticated request verifies:
+
+1. Session exists
+2. Session has not expired
+3. User exists
+4. User status is active
+5. User has required permissions
+
+Failure at any step immediately invalidates access.
+
+---
+
+## Session Revocation
+
+Sessions are revoked when:
+
+* User logs out
+* User is disabled
+* User is deleted
+* Password is reset
+* Administrator revokes sessions
+
+---
+
+## Session Fixation Protection
+
+BZOD generates new session identifiers after successful authentication.
+
+Previously issued identifiers are not reused.
+
+---
+
+# Authorization Model
+
+BZOD implements Role-Based Access Control (RBAC).
+
+Supported roles:
+
+```text
+admin
+standard
+system
+```
+
+---
+
+## Administrator
+
+Administrators can:
+
+* Manage users
+* Reset passwords
+* Transfer ownership
+* Manage quotas
+* Access audit logs
+* Review analytics
+* Create backups
+* Restore backups
+* Moderate content
+
+Administrators cannot bypass audit logging.
+
+---
+
+## Standard User
+
+Standard users can:
+
+* Manage owned URLs
+* Manage owned landing pages
+* View owned analytics
+* Generate API tokens
+* Manage owned content
+
+Standard users cannot:
+
+* Access other users' content
+* Access administrative endpoints
+* Access system settings
+
+---
+
+## System Accounts
+
+System accounts are internal accounts.
+
+They cannot authenticate into:
+
+* Dashboard
+* REST API
+
+---
+
+# Multi-User Isolation
+
+Multi-user isolation is one of the primary security features of BZOD.
+
+Each tenant receives independent databases.
+
+Example:
+
+```text
+users/
+├── 2/
+│   ├── content.db
+│   └── analytics.db
+│
+├── 3/
+│   ├── content.db
+│   └── analytics.db
+```
+
+User 2 never accesses:
+
+```text
+users/3/content.db
+users/3/analytics.db
+```
+
+User 3 never accesses:
+
+```text
+users/2/content.db
+users/2/analytics.db
+```
+
+---
+
+# Global Slug Security
+
+All public slugs are stored in:
+
+```text
+system.db.global_slugs
+```
+
+Each slug is globally unique.
+
+Example:
+
+```text
+/company
+```
+
+may belong to only one owner.
+
+Duplicate registrations are rejected.
+
+---
+
+## Slug Ownership
+
+Every slug contains:
+
+```text
+owner_user_id
+target_id
+target_type
+status
+```
+
+Ownership must match before modification is permitted.
+
+---
+
+## Slug Transfer Protection
+
+Only administrators may transfer ownership.
+
+Transfer operations:
+
+1. Validate destination quotas
+2. Validate destination user
+3. Copy content
+4. Update ownership
+5. Record history
+6. Write audit event
+
+---
+
+# API Security
+
+REST API authentication uses API tokens.
+
+Tokens are stored as hashes.
+
+Plaintext tokens are shown only once during creation.
+
+---
+
+## API Token Security
+
+Stored values:
+
+```text
+token_hash
+```
+
+Never:
+
+```text
+plaintext_token
+```
+
+If a token is lost:
+
+1. Revoke it
+2. Generate a new token
+
+---
+
+## API Permissions
+
+Admin tokens:
+
+```text
+Full administrative access
+```
+
+Standard user tokens:
+
+```text
+Owned resources only
+```
+
+System accounts:
+
+```text
+API access denied
+```
+
+---
+
+# CSRF Protection
+
+All dashboard forms require valid CSRF tokens.
+
+Protected actions include:
+
+* Login
+* User creation
+* Password reset
+* Content modification
+* Moderation actions
+* Quota updates
+* Backup operations
+
+---
+
+## Invalid CSRF Requests
+
+Invalid requests return:
+
+```http
+403 Forbidden
+```
+
+and are rejected before processing.
+
+---
+
+# XSS Protection
+
+User-supplied content is validated before rendering.
+
+Templates use:
+
+```text
+Askama
+```
+
+which escapes output by default.
+
+Recommended:
+
+* Do not allow arbitrary JavaScript
+* Validate HTML content
+* Restrict trusted editors
+
+---
+
+# Content Moderation
+
+Administrators may:
+
+* Flag content
+* Disable content
+* Delete content
+
+Disabled content returns:
+
+```http
+410 Gone
+```
+
+for:
+
+```text
+/{slug}
+/p/{slug}
+/api/qr/{slug}.png
+/api/qr/{slug}.svg
+```
+
+---
+
+# Audit Logging
+
+Security-sensitive actions are logged.
+
+Examples:
+
+```text
+login
+logout
+failed_login
+user_created
+user_deleted
+password_reset
+slug_transfer
+quota_update
+backup_created
+restore_executed
+```
+
+Stored in:
+
+```text
+system.db
+```
+
+Audit logs should be reviewed regularly.
+
+---
+
+# Backup Security
+
+Backups may contain:
+
+* User records
+* Session records
+* URLs
+* Pages
+* Analytics
+* API token hashes
+
+Backups should be treated as sensitive data.
+
+---
+
+## Recommendations
+
+Store backups:
+
+* Offsite
+* Encrypted
+* Access-controlled
+
+Never expose backup archives publicly.
+
+---
+
+# Database Security
+
+SQLite databases should be accessible only to the BZOD service account.
+
+Recommended permissions:
+
+```bash
+chmod 700 data
+chmod 600 *.db
+```
+
+---
+
+# HTTPS Requirements
+
+Production deployments should always use HTTPS.
+
+Recommended reverse proxies:
+
+* Nginx
+* Caddy
+* Traefik
+
+Never expose login pages over plaintext HTTP.
+
+---
+
+# Security Headers
+
+Recommended reverse proxy headers:
+
+```http
+X-Frame-Options: DENY
+X-Content-Type-Options: nosniff
+Referrer-Policy: strict-origin-when-cross-origin
+Content-Security-Policy: default-src 'self'
+```
+
+---
+
+# Password Policy Recommendations
+
+Recommended minimum:
+
+```text
+12 characters
+```
+
+Encourage:
+
+* Password managers
+* Unique passwords
+* Randomly generated credentials
+
+Avoid:
+
+* Reused passwords
+* Dictionary words
+* Predictable patterns
+
+---
+
+# Brute Force Protection
+
+Recommended deployment protections:
+
+* Reverse proxy rate limiting
+* Fail2Ban
+* Firewall rules
+
+Example:
+
+```text
+5 login attempts
+within 5 minutes
+```
+
+before temporary blocking.
+
+---
+
+# Administrative Security Checklist
+
+Before production deployment:
+
+* Enable HTTPS
+* Configure backups
+* Review file permissions
+* Remove default credentials
+* Verify audit logging
+* Test restore procedures
+* Review active sessions
+
+---
+
+# Incident Response
+
+If compromise is suspected:
+
+1. Disable affected accounts.
+2. Revoke active sessions.
+3. Revoke API tokens.
+4. Create forensic backup.
+5. Review audit logs.
+6. Restore from trusted backups if necessary.
+7. Rotate credentials.
+
+---
+
+# Security Testing
+
+BZOD v0.5.0 includes tests covering:
+
+* Authentication
+* Authorization
+* Session validation
+* CSRF enforcement
+* Slug ownership
+* User isolation
+* Upgrade migrations
+* Backup integrity
+* Disaster recovery
+
+These tests are executed during CI and release validation.
+
+---
+
+# Responsible Disclosure
+
+If a security vulnerability is discovered:
+
+1. Do not publish exploit details immediately.
+2. Report the issue privately.
+3. Allow time for remediation.
+4. Coordinate disclosure after a fix is available.
+
+---
+
+# Known Limitations
+
+Current limitations include:
+
+* No MFA support
+* No SSO integration
+* No hardware security key support
+* No built-in rate limiter
+* No WebAuthn support
+
+These may be addressed in future releases.
+
+---
+
+# Summary
+
+BZOD v0.5.0 provides:
+
+* Centralized authentication
+* Secure session management
+* RBAC authorization
+* Multi-user isolation
+* Global slug ownership controls
+* CSRF protection
+* API token hashing
+* Audit logging
+* Backup security
+* Operational security guidance
+
+while maintaining a lightweight, SQLite-native, self-hosted architecture.
+
+---
+
+End of Document.

docs/UPGRADE.md

@@ -0,0 +1,473 @@
+# Upgrade Guide
+
+Version: v0.5.0
+
+This document describes the upgrade process from previous BZOD releases to BZOD v0.5.0.
+
+---
+
+# Overview
+
+BZOD v0.5.0 introduces the largest architectural change in project history:
+
+* Multi-user architecture
+* Tenant isolation
+* Global slug namespace
+* Centralized authentication
+* User quotas
+* User-specific analytics
+* Administrative user management
+* Backup and restore framework
+
+Existing v0.4.x deployments can be upgraded without data loss.
+
+---
+
+# Supported Upgrade Paths
+
+Supported:
+
+```text
+v0.4.0  → v0.5.0
+v0.4.x  → v0.5.0
+```
+
+Unsupported:
+
+```text
+v0.3.x → v0.5.0
+```
+
+Older installations should first upgrade to v0.4.x.
+
+---
+
+# Breaking Changes
+
+## Database Layout
+
+### v0.4.x
+
+```text
+data/
+├── admin.db
+├── content.db
+└── analytics.db
+```
+
+### v0.5.0
+
+```text
+data/
+├── users.db
+├── system.db
+└── users/
+    └── 1/
+        ├── content.db
+        └── analytics.db
+```
+
+---
+
+## Authentication
+
+Authentication is now centralized.
+
+Old:
+
+```text
+admin.db
+```
+
+New:
+
+```text
+users.db
+```
+
+Sessions are managed globally.
+
+---
+
+## Global Slug Namespace
+
+Slugs are now unique platform-wide.
+
+Examples:
+
+```text
+/example
+/company
+/docs
+```
+
+cannot exist twice.
+
+---
+
+# Pre-Upgrade Checklist
+
+Before upgrading:
+
+* Verify current version
+* Stop active traffic
+* Create backup
+* Verify backup integrity
+
+---
+
+## Step 1: Create Backup
+
+CLI:
+
+```bash
+bzod backup
+```
+
+or manually archive:
+
+```bash
+tar czf bzod-backup.tar.gz data/
+```
+
+---
+
+## Step 2: Verify Backup
+
+Confirm archive contains:
+
+```text
+admin.db
+content.db
+analytics.db
+```
+
+---
+
+## Step 3: Stop Service
+
+Systemd:
+
+```bash
+sudo systemctl stop bzod
+```
+
+Docker:
+
+```bash
+docker compose down
+```
+
+---
+
+# Upgrade Procedure
+
+## Replace Binary
+
+Install new release:
+
+```bash
+cargo build --release
+```
+
+or download release binary.
+
+---
+
+## Start BZOD
+
+```bash
+bzod serve
+```
+
+On first startup BZOD automatically:
+
+1. Detects legacy databases.
+2. Creates users.db.
+3. Creates system.db.
+4. Creates administrator tenant.
+5. Moves content.db.
+6. Moves analytics.db.
+7. Creates global slug registry.
+8. Runs migrations.
+
+---
+
+# Automatic Migration
+
+Migration performs:
+
+## Administrator Creation
+
+Legacy administrator becomes:
+
+```text
+User ID: 1
+Type: admin
+```
+
+---
+
+## Content Migration
+
+All URLs migrate into:
+
+```text
+users/1/content.db
+```
+
+---
+
+## Analytics Migration
+
+All analytics migrate into:
+
+```text
+users/1/analytics.db
+```
+
+---
+
+## Global Slug Registration
+
+All existing slugs are inserted into:
+
+```text
+system.db.global_slugs
+```
+
+---
+
+# Post-Upgrade Validation
+
+## Login
+
+Verify:
+
+```text
+Admin login succeeds
+```
+
+---
+
+## URLs
+
+Verify:
+
+```text
+Short URLs redirect
+```
+
+Example:
+
+```text
+https://example.com/abc123
+```
+
+---
+
+## Landing Pages
+
+Verify:
+
+```text
+https://example.com/p/demo
+```
+
+renders correctly.
+
+---
+
+## Analytics
+
+Verify:
+
+* Visits visible
+* Reports load
+* Charts render
+
+---
+
+## User Management
+
+Verify:
+
+```text
+Admin → Users
+```
+
+loads correctly.
+
+---
+
+# Upgrade Validation Tests
+
+BZOD v0.5.0 includes automated migration tests.
+
+Validated:
+
+* Legacy admin migration
+* Legacy content migration
+* Legacy analytics migration
+* Slug registration
+* Redirect preservation
+* Analytics preservation
+
+Test suite:
+
+```bash
+cargo test --test upgrade_validation_tests
+```
+
+---
+
+# Rollback Procedure
+
+If upgrade validation fails:
+
+## Stop Server
+
+```bash
+sudo systemctl stop bzod
+```
+
+or
+
+```bash
+docker compose down
+```
+
+---
+
+## Restore Backup
+
+```bash
+bzod restore backup.zip
+```
+
+or restore archived data directory.
+
+---
+
+## Reinstall Previous Release
+
+Deploy previous v0.4.x binary.
+
+---
+
+# Docker Upgrade
+
+Pull new image:
+
+```bash
+docker compose pull
+```
+
+Restart:
+
+```bash
+docker compose up -d
+```
+
+Monitor logs:
+
+```bash
+docker compose logs -f
+```
+
+Verify migrations complete successfully.
+
+---
+
+# Systemd Upgrade
+
+Replace binary:
+
+```bash
+sudo cp bzod /usr/local/bin/
+```
+
+Restart:
+
+```bash
+sudo systemctl restart bzod
+```
+
+Verify:
+
+```bash
+sudo systemctl status bzod
+```
+
+---
+
+# Recommended Upgrade Workflow
+
+```text
+1. Create backup
+2. Stop service
+3. Install v0.5.0
+4. Start service
+5. Run migrations
+6. Validate login
+7. Validate URLs
+8. Validate analytics
+9. Validate admin dashboard
+10. Return to production
+```
+
+---
+
+# Troubleshooting
+
+## Login Fails
+
+Check:
+
+```text
+users.db
+```
+
+Verify administrator account exists.
+
+---
+
+## URLs Missing
+
+Verify:
+
+```text
+users/1/content.db
+```
+
+contains migrated records.
+
+---
+
+## Analytics Missing
+
+Verify:
+
+```text
+users/1/analytics.db
+```
+
+contains visit data.
+
+---
+
+## Slug Resolution Fails
+
+Verify:
+
+```sql
+SELECT * FROM global_slugs;
+```
+
+returns expected entries.
+
+---
+
+# Upgrade Status
+
+BZOD v0.5.0 upgrade path has been validated through automated migration and integration testing and is considered production-ready for upgrades from v0.4.x deployments.