feat: Add torch system for multi-browser MCP control

- Add TorchButton component to header (replaces dropdowns)
- Add torch store for managing torch state
- Add torch service for requesting/releasing torch
- Add torch event handlers in WebMCP service
- Remove ComponentsDropdown and ToolsDropdown from header

The torch system allows controlling which browser receives
MCP tool calls when multiple browsers are connected.
Requires WebMCP library update to fully function.

frontend/src/App.vue

@@ -3,9 +3,7 @@ import { ref, onMounted, onUnmounted, watch } from 'vue'
 import { RouterView, useRoute, useRouter } from 'vue-router'
 import StatusBar from './components/StatusBar.vue'
 import Toolbar from './components/Toolbar.vue'
-import ComponentsDropdown from './components/ComponentsDropdown.vue'
-import ToolsDropdown from './components/ToolsDropdown.vue'
-// ConnectionDropdown removed - replaced with debug console
+import TorchButton from './components/TorchButton.vue'
 import FloatingTerminal from './components/FloatingTerminal.vue'
 import FloatingResponse from './components/FloatingResponse.vue'
 import FloatingVoice from './components/FloatingVoice.vue'
@@ -366,14 +364,13 @@ watch(() => route.name, (newPage) => {
     <header class="app-header">
       <div class="header-left">
         <h1 class="logo">Agent UI</h1>
+        <TorchButton />
         <button class="debug-btn" :class="{ active: showDebugConsole }" @click="showDebugConsole = !showDebugConsole" title="Debug Console">
           <svg xmlns="http://www.w3.org/2000/svg" width="14" height="14" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2">
             <path d="M12 20h9"/><path d="M16.5 3.5a2.121 2.121 0 0 1 3 3L7 19l-4 1 1-4L16.5 3.5z"/>
           </svg>
           <span v-if="debugLogs.length" class="log-count">{{ debugLogs.length }}</span>
         </button>
-        <ComponentsDropdown />
-        <ToolsDropdown />
         <PwaInstallBanner />
       </div>
       <button class="refresh-btn" @click="hardRefresh" title="Hard refresh (Ctrl+F5)">