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-network/src/lib.rs

@@ -0,0 +1,11 @@
+//! Route, firewall, and network management for nx9-wg.
+
+pub mod engine;
+pub mod error;
+pub mod forwarding;
+pub mod nftables;
+
+pub use engine::{NativeLinuxNetworkEngine, NetworkEngine, SimulatedNetworkEngine};
+pub use error::{NetworkError, Result};
+pub use forwarding::IpForwardingStatus;
+pub use nftables::NftablesRulesetBuilder;