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/stores/torch.ts

@@ -0,0 +1,72 @@
+import { defineStore } from 'pinia'
+import { ref, computed } from 'vue'
+
+export interface TorchClient {
+  id: string
+  userAgent: string
+  hostname: string
+  url: string
+  connectedAt: string
+  hasTorch: boolean
+}
+
+export const useTorchStore = defineStore('torch', () => {
+  // State
+  const clientId = ref<string | null>(null)
+  const hasTorch = ref(false)
+  const torchHolderId = ref<string | null>(null)
+  const clients = ref<TorchClient[]>([])
+  const isRequesting = ref(false)
+
+  // Computed
+  const isConnected = computed(() => clientId.value !== null)
+  const torchHolder = computed(() => clients.value.find(c => c.hasTorch))
+
+  // Actions
+  function setClientId(id: string) {
+    clientId.value = id
+  }
+
+  function setTorchState(holder: string | null) {
+    torchHolderId.value = holder
+    hasTorch.value = holder === clientId.value
+  }
+
+  function setClients(newClients: TorchClient[]) {
+    clients.value = newClients
+    // Update torch state based on clients
+    const holder = newClients.find(c => c.hasTorch)
+    torchHolderId.value = holder?.id || null
+    hasTorch.value = holder?.id === clientId.value
+  }
+
+  function setRequesting(value: boolean) {
+    isRequesting.value = value
+  }
+
+  function reset() {
+    clientId.value = null
+    hasTorch.value = false
+    torchHolderId.value = null
+    clients.value = []
+    isRequesting.value = false
+  }
+
+  return {
+    // State
+    clientId,
+    hasTorch,
+    torchHolderId,
+    clients,
+    isRequesting,
+    // Computed
+    isConnected,
+    torchHolder,
+    // Actions
+    setClientId,
+    setTorchState,
+    setClients,
+    setRequesting,
+    reset
+  }
+})