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/tailscale/Panel.qml

@@ -373,6 +373,7 @@ Panel {
     function refresh(): string { tailscale.refresh(); return "ok" }
     function up(): string { tailscale.loginOrUp(); return "ok" }
     function down(): string { tailscale.down(); return "ok" }
+    function toggleTailscale(): string { tailscale.toggleTailscale(); return "ok" }
     function status(): string { return tailscale.statusText }
   }