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-db/Cargo.toml

@@ -0,0 +1,20 @@
+[package]
+name = "nx9-wg-db"
+description = "SQLite persistence layer for nx9-wg"
+version.workspace = true
+edition.workspace = true
+
+[dependencies]
+nx9-wg-core.workspace = true
+sqlx = { workspace = true, features = ["runtime-tokio", "sqlite", "macros", "migrate", "chrono", "uuid"] }
+tokio.workspace = true
+chrono.workspace = true
+uuid.workspace = true
+ipnet.workspace = true
+thiserror.workspace = true
+tracing.workspace = true
+serde.workspace = true
+serde_json.workspace = true
+
+[dev-dependencies]
+tempfile.workspace = true