feat: Add WebMCP token polling for automatic browser connection

- Add token API endpoint to server for storing/retrieving pending tokens
- Add token polling in frontend to auto-detect and connect with tokens
- Add xterm dependencies for terminal functionality
- Add terminal page support in toolRegistry

frontend/src/services/webmcp.ts

@@ -3,6 +3,9 @@ import { useCanvasStore } from '../stores/canvas'
 let webmcpInstance: any = null
 const registeredTools = new Set<string>()
 
+const API_BASE = 'http://localhost:4101'
+let tokenPollingInterval: number | null = null
+
 export async function initWebMCP() {
   if (webmcpInstance) return webmcpInstance
 
@@ -95,3 +98,80 @@ export function getRegisteredTools(): string[] {
 export function isToolRegistered(name: string): boolean {
   return registeredTools.has(name)
 }
+
+// Token polling functions
+export async function checkForToken(): Promise<string | null> {
+  try {
+    const res = await fetch(`${API_BASE}/api/webmcp-token`)
+    const data = await res.json()
+    return data.token || null
+  } catch (e) {
+    return null
+  }
+}
+
+export async function clearToken(): Promise<void> {
+  try {
+    await fetch(`${API_BASE}/api/webmcp-token`, { method: 'DELETE' })
+  } catch (e) {
+    // ignore
+  }
+}
+
+export function startTokenPolling(onToken: (token: string) => void, intervalMs: number = 2000) {
+  if (tokenPollingInterval) return
+
+  console.log('[WebMCP] Starting token polling...')
+  tokenPollingInterval = window.setInterval(async () => {
+    const token = await checkForToken()
+    if (token) {
+      console.log('[WebMCP] Token detected!')
+      stopTokenPolling()
+      onToken(token)
+    }
+  }, intervalMs)
+}
+
+export function stopTokenPolling() {
+  if (tokenPollingInterval) {
+    window.clearInterval(tokenPollingInterval)
+    tokenPollingInterval = null
+    console.log('[WebMCP] Token polling stopped')
+  }
+}
+
+export function parseToken(token: string): { server: string; token: string } | null {
+  try {
+    const decoded = atob(token)
+    return JSON.parse(decoded)
+  } catch (e) {
+    console.error('[WebMCP] Failed to parse token:', e)
+    return null
+  }
+}
+
+export async function connectWithToken(token: string): Promise<boolean> {
+  const parsed = parseToken(token)
+  if (!parsed) return false
+
+  console.log('[WebMCP] Connecting with token to:', parsed.server)
+
+  // Store token for webmcp to use
+  localStorage.setItem('webmcp_token', token)
+
+  // Clear the pending token from server
+  await clearToken()
+
+  // If webmcp is already initialized, try to reconnect
+  if (webmcpInstance && typeof webmcpInstance.connect === 'function') {
+    try {
+      await webmcpInstance.connect()
+      return true
+    } catch (e) {
+      console.error('[WebMCP] Failed to connect:', e)
+      return false
+    }
+  }
+
+  return true
+}