Fix auth: auto-create customer, display name flow, OTP auto-verify

- Backend: getOrCreateCustomer with phone fallback for re-login
- Backend: PATCH /api/client/auth/profile for display name update
- Client app: AuthNeedsDisplayNameData state + SetDisplayNameScreen
- Client app: ApiClient.patch method
- Both apps: handle verificationCompleted for auto-verify (test numbers)
- Both apps: skip credential sign-in if already auto-verified
- Remove debug prints from mitra auth + OTP screens
- Fix ChatRequestNotifier.startListening skips when accepting

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

backend/src/routes/public/client.auth.routes.js

@@ -1,8 +1,18 @@
 import { authenticate } from '../../plugins/auth.js'
-import { getCustomerByFirebaseUid } from '../../services/customer.service.js'
+import { getOrCreateCustomer, getCustomerByFirebaseUid, updateCustomerDisplayName } from '../../services/customer.service.js'
 
 export const clientAuthRoutes = async (app) => {
   app.post('/verify', { preHandler: authenticate }, async (request, reply) => {
+    const { uid, phone_number, name } = request.firebaseUser
+    const customer = await getOrCreateCustomer({
+      firebase_uid: uid,
+      phone: phone_number || null,
+      display_name: name || null,
+    })
+    return reply.send({ success: true, data: customer })
+  })
+
+  app.patch('/profile', { preHandler: authenticate }, async (request, reply) => {
     const customer = await getCustomerByFirebaseUid(request.firebaseUser.uid)
     if (!customer) {
       return reply.code(404).send({
@@ -10,6 +20,14 @@ export const clientAuthRoutes = async (app) => {
         error: { code: 'NOT_FOUND', message: 'Customer account not found' },
       })
     }
-    return reply.send({ success: true, data: customer })
+    const { display_name } = request.body || {}
+    if (!display_name || typeof display_name !== 'string' || display_name.trim().length === 0) {
+      return reply.code(422).send({
+        success: false,
+        error: { code: 'VALIDATION_ERROR', message: 'display_name is required' },
+      })
+    }
+    const updated = await updateCustomerDisplayName(customer.id, display_name.trim())
+    return reply.send({ success: true, data: updated })
   })
 }