Dim and sleep locked displays after inactivity

Add adjustable lock-only inactivity delays, a smooth dimming fade and DRM display sleep without changing output layout. Input, session resume and policy changes wake displays. Pending flips retire before power-off, and protected fallback frames preserve the policy after an early locker crash while unlock ownership checks remain strict.

Reduce the password field and avatar, expose delays in Settings, document the practical swaylock comparison and remove the completed backlog.

Validation: independent review cleared; 255 compositor tests, 7 locker tests and 15 Settings tests pass; affected debug binaries rebuilt. Isolated visual smoke remains blocked by an unlocked nested screenshot timeout, matching the previously established baseline presentation limitation. Real DRM display sleep requires a live session check.

compositor/src/state.rs

@@ -226,6 +226,7 @@ impl ClosingAnimation {
 pub struct Ferese {
     pub(crate) session_lock_state: smithay::wayland::session_lock::SessionLockManagerState,
     pub(crate) session_lock: crate::session_lock::Lock,
+    pub(crate) lock_idle: crate::session_lock::IdleSettings,
     pub(crate) config_source: Option<String>,
     pub start_time: Instant,
     pub socket_name: OsString,
@@ -353,6 +354,7 @@ pub struct Ferese {
 }
 
 pub struct RuntimeConfig {
+    pub(crate) lock_idle: crate::session_lock::IdleSettings,
     pub(crate) autostart: Vec<crate::config::DaemonConfig>,
     pub(crate) overview_font_family: String,
     pub(crate) wallpaper: crate::wallpaper::WallpaperConfig,
@@ -447,6 +449,7 @@ impl Ferese {
         let mut state = Self {
             session_lock_state,
             session_lock: crate::session_lock::Lock::default(),
+            lock_idle: config.lock_idle,
             config_source: None,
             start_time,
             socket_name,
@@ -609,6 +612,7 @@ impl Ferese {
             );
         }
 
+        self.lock_idle = config.lock_idle;
         self.advance_animations(Instant::now());
 
         let touchpad_changed = self.input_settings.touchpad != config.input_settings.touchpad;
@@ -677,6 +681,10 @@ impl Ferese {
     }
 
     pub fn register_output(&mut self, output: &Output, identity: String) {
+        if self.session_lock.active {
+            self.session_lock.output_added(output);
+            self.lock_input_activity();
+        }
         let Some(geometry) = self.space.output_geometry(output) else {
             tracing::error!(output = %output.name(), "cannot register an unmapped output");
             return;
@@ -738,6 +746,7 @@ impl Ferese {
         self.space.unmap_output(output);
         self.session_lock.surfaces.remove(output);
         self.session_lock.backgrounds.remove(output);
+        self.session_lock.output_removed(output);
 
         match self.output_workspaces.disconnect(output_id) {
             Ok(Some(target)) => {