Add automatic idle inhibition for fullscreen playback and selected apps

docs/configuration.md

@@ -534,6 +534,7 @@ window rules can override that behavior.
 | `width`, `height` | numbers > 0 | Application-chosen floating size |
 | `fullscreen` | boolean | Leave fullscreen state unchanged |
 | `block-out-from-screencasts` | boolean | Exclude from captures; enabled by default for Ferese authentication dialogs |
+| `idle-inhibit` | `none`, `visible`, `fullscreen`, `playing`, `fullscreen-playing` | Automatic fullscreen playback; see [Idle inhibition](#idle-inhibition) |
 
 `window-rule app-id="org.example.Private" block-out-from-screencasts=#true`
 keeps matching windows visible on the display but omits them (including their
@@ -574,7 +575,9 @@ Transient dialogs and cancelled drags do not update this memory. Floating → ti
 → floating also restores the window's last floating geometry. Nested previews
 keep drag memory in process and do not write the user's saved placements.
 
-Title changes do not trigger new rules; config rule changes apply to existing windows.
+Title changes do not reapply placement rules. Capture privacy and idle inhibition
+follow current app ID, title and parent metadata. Config rule changes apply to
+existing windows.
 
 ```kdl
 window-rule app-id="dev.ferese.Settings" floating=#true
@@ -776,6 +779,49 @@ unlock in a nested compositor before enabling automatic locking. A crashed
 locker leaves the session locked; recovery requires ending that session from
 another TTY.
 
+## Idle inhibition
+
+Ferese keeps the session awake during fullscreen playback when an application
+reports `Playing` through MPRIS. Pausing or stopping playback releases this
+automatic inhibition. A window must have content visible on an awake display;
+switching away, closing it, locking the session or sleeping its display releases
+inhibition too.
+
+Disable the default fullscreen playback policy with:
+
+```kdl
+idle-inhibit {
+    fullscreen-playback #false
+}
+```
+
+Use window rules for presentations, games or other apps that should keep the
+session awake while visible:
+
+```kdl
+window-rule app-id="org.example.Presentation" idle-inhibit="visible"
+```
+
+| `idle-inhibit` rule | Behavior |
+| --- | --- |
+| `visible` | Inhibit while visible, regardless of playback state |
+| `fullscreen` | Inhibit while visible and fullscreen |
+| `playing` | Inhibit while visible and its MPRIS player reports `Playing` |
+| `fullscreen-playing` | Inhibit while visible, fullscreen and its MPRIS player reports `Playing` |
+| `none` | Disable automatic inhibition for this window |
+
+MPRIS identifies an application, not an individual video window. Ferese matches
+the player's process ID first, then its `DesktopEntry` against the window's app
+ID. If several windows match, automatic playback inhibition stays off. MPRIS
+also does not distinguish audio from video, so fullscreen audio playback can
+inhibit too. Players without MPRIS can request inhibition through the existing
+Wayland or portal protocols; a fullscreen window alone does not prove playback.
+
+These settings control automatic inhibition. They do not override an
+application's own Wayland or portal request, and they do not block manual
+locking or suspend. Run `feresectl get-idle-inhibition` to inspect the current
+inhibition state and discovered players. Changes take effect on config reload.
+
 ## Optional session protocols
 
 These are launch-time environment switches, not KDL keys. Enable only for