cli: avoid data-dir initialization for version; create db parent dirs; redact generated passwords in CLI output

- Prevent 'nx9-wg version' from creating data directories by avoiding database initialization.
- Create parent directories when an explicit --database path is provided.
- Redact printed generated administrator passwords; announce file path or redact instead.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

crates/nx9-wg-core/Cargo.toml

@@ -0,0 +1,23 @@
+[package]
+name = "nx9-wg-core"
+description = "Core domain types, configuration, and utilities for nx9-wg"
+version.workspace = true
+edition.workspace = true
+
+[dependencies]
+serde.workspace = true
+serde_json.workspace = true
+toml.workspace = true
+chrono.workspace = true
+uuid.workspace = true
+thiserror.workspace = true
+tracing.workspace = true
+argon2.workspace = true
+x25519-dalek.workspace = true
+rand.workspace = true
+base64.workspace = true
+sha2.workspace = true
+ipnet.workspace = true
+
+[dev-dependencies]
+tempfile.workspace = true