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>

test/shell.d/bar-test.sh

@@ -18,6 +18,9 @@ run_node_test <<'JS'
 const fs = require('fs')
 const bar = requireFromRoot('shell/plugins/bar/BarModel.js')
 const barSource = fs.readFileSync(root + '/shell/plugins/bar/Bar.qml', 'utf8')
+const shellSource = fs.readFileSync(root + '/shell/shell.qml', 'utf8')
+
+assert(/function toggleBarTransparency\(\): string \{[\s\S]*?shell\.bar\.toggleTransparency\(\)/.test(shellSource), 'shell exposes the bar transparency toggle over IPC')
 
 // The center section declares two arrangements and shows one; the hidden one
 // must not build its modules or every center widget exists twice.