Handle volume, media and notification keys in the shell (#13424)

* Step the volume in the shell instead of a script per keypress

Each volume key ran omarchy-audio-output-volume: several pactl calls in
bash, then omarchy-osd delivering the OSD over a qs IPC client, ~165ms
from keypress to OSD, on keys that repeat while held.

The volume up, down and mute keys now dispatch global shortcuts that the
media service handles over PipeWire, stepping, clamping, unmuting and
debouncing by the script's rules and showing the same OSD. It acts only
when the default sink is an ALSA sink, which is its own physical sink.
Any other default, a DSP chain or EasyEffects above all, falls back to
the script, which resolves the physical sink from the live routing on
every press. The precise +1/-1 keys still run the script.

Keypress to OSD drops from ~168ms to ~20ms.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

* Run media and notification keys in the shell without an IPC client

The media keys and the notification dismiss, invoke and history keys ran
omarchy-shell, starting a qs client for one argument-free IPC call.

A new ipc shortcut kind names such a call as target.method. The shell
hands it to the service that owns the target, which runs its own
IpcHandler function, so the key behaves exactly as the omarchy-shell
call did. A call missing from the list binds through omarchy-shell.

Dismissing a notification with SUPER+comma clears the popup in ~11ms
instead of ~40ms.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

---------

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

shell/plugins/notifications/Service.qml

@@ -854,7 +854,16 @@ Item {
 
   // ---------------------------------------------------- IPC
 
+  // Keybindings reach these handlers as Hyprland global shortcuts, run here
+  // exactly as the IPC call would run them, with no client to spawn.
+  function runShortcut(method) {
+    if (typeof ipcHandler[method] !== "function") return false
+    ipcHandler[method]()
+    return true
+  }
+
   IpcHandler {
+    id: ipcHandler
     target: "notifications"
 
     function dndState(): string {