Add pending chat requests CTA on mitra home screen

- Backend: new GET /api/mitra/chat-requests/pending endpoint
- Backend: getPendingRequestsForMitra() queries unresponded notifications
  for sessions still in pending_acceptance status
- Mitra app: loadPendingRequests() fetches on screen load + status toggle
- Mitra app: activeRequestCount getter exposes queue size
- Mitra app: _PendingRequestsBanner widget shows count with tap-to-view

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/src/routes/public/mitra.chat.routes.js

@@ -1,6 +1,6 @@
 import { authenticate } from '../../plugins/auth.js'
 import { getMitraByFirebaseUid } from '../../services/mitra.service.js'
-import { acceptPairingRequest, declinePairingRequest, getSessionStatus } from '../../services/pairing.service.js'
+import { acceptPairingRequest, declinePairingRequest, getSessionStatus, getPendingRequestsForMitra } from '../../services/pairing.service.js'
 import { getActiveSessionsByMitra, getActiveSessionsByMitraWithUnread, endSession, getMitraHistory } from '../../services/session.service.js'
 import { respondToExtension } from '../../services/extension.service.js'
 import { EndedBy } from '../../constants.js'
@@ -23,6 +23,12 @@ const resolveMitra = async (request, reply) => {
 }
 
 export const mitraChatRoutes = async (app) => {
+  // Get pending chat requests for this mitra
+  app.get('/pending', { preHandler: [authenticate, resolveMitra] }, async (request, reply) => {
+    const requests = await getPendingRequestsForMitra(request.mitra.id)
+    return reply.send({ success: true, data: requests })
+  })
+
   // Check if a session is still pending acceptance (for notification validation)
   app.get('/:sessionId/status', { preHandler: [authenticate, resolveMitra] }, async (request, reply) => {
     const session = await getSessionStatus(request.params.sessionId)