Expose the shell's remaining UI-only toggles over IPC

Every toggle you could only reach by mouse or panel hotkey is now
scriptable through omarchy-shell:

- omarchy.bluetooth toggleBluetooth — the radio (was right-click / B)
- omarchy.network toggleNetwork — Wi-Fi on/off (was W in the panel)
- omarchy.tailscale toggleTailscale — the connection as one call,
  matching the widget's right-click, instead of separate up/down
- omarchy.clock toggleWeekStart — calendar week start (was W)
- shell toggleBarTransparency — the bar background (was manage UI only)

Bluetooth and network follow the power/monitor pattern: manageIpc: false
so the panel owns the target's single IpcHandler and can extend it past
the inherited lifecycle methods.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

shell/plugins/panels/bluetooth/Panel.qml

@@ -12,6 +12,9 @@ Panel {
   id: root
   moduleName: "omarchy.bluetooth"
   ipcTarget: "omarchy.bluetooth"
+  // manageIpc: false so this panel can own the single IpcHandler the target
+  // permits — needed for the toggleBluetooth method below.
+  manageIpc: false
 
   // Address -> "connecting" | "disconnecting" | "forgetting".
   // The actual Bluetooth sequencing lives in bin/omarchy-bluetooth-device;
@@ -515,6 +518,17 @@ Panel {
     adapter.enabled = !adapter.enabled
   }
 
+  IpcHandler {
+    target: "omarchy.bluetooth"
+
+    function open() { root.open() }
+    function close() { root.close() }
+    function show() { root.open() }
+    function hide() { root.close() }
+    function toggle() { root.toggle() }
+    function toggleBluetooth() { root.toggleBluetooth() }
+  }
+
   BarIconButton {
     id: button
     anchors.fill: parent