Phase 3 scaffold: chat engine (WebSocket, FCM, pricing, timer, extension, history)

- Backend: WebSocket plugin, chat/pricing/timer/extension/closure/notification services
- Client app: ChatBloc, pricing dialog, chat screen with message status, extension/goodbye flow, history
- Mitra app: MitraChatBloc, ExtensionBloc, chat screen, extension accept/reject, history
- Control center: free trial, extension timeout, early end config toggles
- DB migration: chat_messages, session_closures, session_extensions, customer_transactions tables

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

backend/src/routes/internal/config.routes.js

@@ -1,6 +1,12 @@
 import { authenticate, requirePermission } from '../../plugins/auth.js'
 import { getCcUserByFirebaseUid } from '../../services/cc-user.service.js'
-import { getAnonymityConfig, setAnonymityConfig, getMaxCustomersPerMitra, setMaxCustomersPerMitra } from '../../services/config.service.js'
+import {
+  getAnonymityConfig, setAnonymityConfig,
+  getMaxCustomersPerMitra, setMaxCustomersPerMitra,
+  getFreeTrialConfig, setFreeTrialConfig,
+  getExtensionTimeoutConfig, setExtensionTimeoutConfig,
+  getEarlyEndConfig, setEarlyEndConfig,
+} from '../../services/config.service.js'
 
 const attachCcUser = async (request, reply) => {
   const user = await getCcUserByFirebaseUid(request.firebaseUser.uid)
@@ -44,4 +50,55 @@ export const internalConfigRoutes = async (app) => {
     const config = await setMaxCustomersPerMitra(max_customers_per_mitra)
     return reply.send({ success: true, data: config })
   })
+
+  // --- Phase 3: Free Trial ---
+  app.get('/free-trial', {
+    preHandler: [authenticate, attachCcUser, requirePermission('config', 'read')],
+  }, async (request, reply) => {
+    const config = await getFreeTrialConfig()
+    return reply.send({ success: true, data: config })
+  })
+
+  app.patch('/free-trial', {
+    preHandler: [authenticate, attachCcUser, requirePermission('config', 'update')],
+  }, async (request, reply) => {
+    const { enabled, duration_minutes } = request.body ?? {}
+    const config = await setFreeTrialConfig({ enabled, duration_minutes })
+    return reply.send({ success: true, data: config })
+  })
+
+  // --- Phase 3: Extension Timeout ---
+  app.get('/extension-timeout', {
+    preHandler: [authenticate, attachCcUser, requirePermission('config', 'read')],
+  }, async (request, reply) => {
+    const config = await getExtensionTimeoutConfig()
+    return reply.send({ success: true, data: config })
+  })
+
+  app.patch('/extension-timeout', {
+    preHandler: [authenticate, attachCcUser, requirePermission('config', 'update')],
+  }, async (request, reply) => {
+    const { extension_timeout_seconds } = request.body ?? {}
+    if (typeof extension_timeout_seconds !== 'number' || extension_timeout_seconds < 10) {
+      return reply.code(422).send({ success: false, error: { code: 'VALIDATION_ERROR', message: 'Must be a number >= 10' } })
+    }
+    const config = await setExtensionTimeoutConfig(extension_timeout_seconds)
+    return reply.send({ success: true, data: config })
+  })
+
+  // --- Phase 3: Early End ---
+  app.get('/early-end', {
+    preHandler: [authenticate, attachCcUser, requirePermission('config', 'read')],
+  }, async (request, reply) => {
+    const config = await getEarlyEndConfig()
+    return reply.send({ success: true, data: config })
+  })
+
+  app.patch('/early-end', {
+    preHandler: [authenticate, attachCcUser, requirePermission('config', 'update')],
+  }, async (request, reply) => {
+    const { mitra_enabled, customer_enabled } = request.body ?? {}
+    const config = await setEarlyEndConfig({ mitra_enabled, customer_enabled })
+    return reply.send({ success: true, data: config })
+  })
 }