PAM conv callback: check msg_style (password only for ECHO_OFF),
handle strdup OOM with proper cleanup, null-check PAM handle.
Fingerprint: self-wire D-Bus g-signal in start() via Rc<RefCell<>>
and connect_local — VerifyStatus signals are now actually dispatched.
VerifyStop before VerifyStart in restart_verify.
Lockscreen: password entry stays active after faillock threshold
(PAM decides lockout, not UI), use Zeroizing<String> from GTK entry.
Release builds exit(1) without ext-session-lock-v1 support.
Config: fingerprint_enabled as Option<bool> so empty user config
does not override system config.
Dead code: remove unused i18n strings and fingerprint accessors,
parameterize faillock_warning max_attempts.
Complete rewrite of the Wayland lockscreen from Python/PyGObject to
Rust/gtk4-rs for memory safety in security-critical PAM code and
consistency with the moonset/moongreet Rust ecosystem.
Modules: main, lockscreen, auth (PAM FFI), fingerprint (fprintd D-Bus),
config, i18n, users, power. 37 unit tests.
Security: PAM conversation callback with Zeroizing password, panic hook
that never unlocks, root check, ext-session-lock-v1 compositor policy,
absolute loginctl path, avatar symlink rejection.
