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/public/client.chat.routes.js

@@ -1,8 +1,10 @@
 import { authenticate } from '../../plugins/auth.js'
 import { getCustomerByFirebaseUid } from '../../services/customer.service.js'
 import { createPairingRequest, cancelPairingRequest, getSessionStatus } from '../../services/pairing.service.js'
-import { getActiveSessionByCustomer, endSession } from '../../services/session.service.js'
+import { getActiveSessionByCustomer, endSession, getCustomerHistory } from '../../services/session.service.js'
 import { subscribe } from '../../plugins/valkey.js'
+import { getPricingForCustomer, isValidTier, isCustomerEligibleForFreeTrial, getFreeTrial } from '../../services/pricing.service.js'
+import { requestExtension } from '../../services/extension.service.js'
 
 const resolveCustomer = async (request, reply) => {
   const customer = await getCustomerByFirebaseUid(request.firebaseUser.uid)
@@ -16,8 +18,48 @@ const resolveCustomer = async (request, reply) => {
 }
 
 export const clientChatRoutes = async (app) => {
+  // Get pricing tiers + free trial eligibility
+  app.get('/pricing', { preHandler: [authenticate, resolveCustomer] }, async (request, reply) => {
+    const pricing = await getPricingForCustomer(request.customer.id)
+    return reply.send({ success: true, data: pricing })
+  })
+
   app.post('/request', { preHandler: [authenticate, resolveCustomer] }, async (request, reply) => {
-    const session = await createPairingRequest(request.customer.id)
+    const { duration_minutes, price, is_free_trial } = request.body || {}
+
+    // Validate selection
+    if (is_free_trial) {
+      const eligible = await isCustomerEligibleForFreeTrial(request.customer.id)
+      if (!eligible) {
+        return reply.code(403).send({
+          success: false,
+          error: { code: 'FREE_TRIAL_INELIGIBLE', message: 'Not eligible for free trial' },
+        })
+      }
+      const freeTrial = await getFreeTrial()
+      const session = await createPairingRequest(request.customer.id, {
+        duration_minutes: freeTrial.duration_minutes,
+        price: 0,
+        is_free_trial: true,
+      })
+      return reply.code(201).send({ success: true, data: session })
+    }
+
+    if (!duration_minutes || price === undefined) {
+      return reply.code(400).send({
+        success: false,
+        error: { code: 'BAD_REQUEST', message: 'duration_minutes and price are required' },
+      })
+    }
+
+    if (!isValidTier(duration_minutes, price)) {
+      return reply.code(400).send({
+        success: false,
+        error: { code: 'INVALID_TIER', message: 'Invalid price tier selection' },
+      })
+    }
+
+    const session = await createPairingRequest(request.customer.id, { duration_minutes, price, is_free_trial: false })
     return reply.code(201).send({ success: true, data: session })
   })
 
@@ -72,4 +114,27 @@ export const clientChatRoutes = async (app) => {
     const session = await endSession(request.params.sessionId, 'customer')
     return reply.send({ success: true, data: session })
   })
+
+  // Request session extension
+  app.post('/session/:sessionId/extend', { preHandler: [authenticate, resolveCustomer] }, async (request, reply) => {
+    const { duration_minutes, price } = request.body || {}
+    if (!duration_minutes || price === undefined) {
+      return reply.code(400).send({
+        success: false,
+        error: { code: 'BAD_REQUEST', message: 'duration_minutes and price are required' },
+      })
+    }
+    const extension = await requestExtension(request.params.sessionId, request.customer.id, { duration_minutes, price })
+    return reply.send({ success: true, data: extension })
+  })
+
+  // Chat history
+  app.get('/history', { preHandler: [authenticate, resolveCustomer] }, async (request, reply) => {
+    const { page, limit } = request.query
+    const history = await getCustomerHistory(request.customer.id, {
+      page: page ? parseInt(page) : 1,
+      limit: limit ? parseInt(limit) : 20,
+    })
+    return reply.send({ success: true, data: history })
+  })
 }