Phase 3.1: Complete mitra_app Riverpod migration (all blocs, fix auth bug)

- Migrate AuthBloc → MitraAuthNotifier (fixes stuck-loading bug: now returns
  MitraAuthInitialData when currentUser is null)
- Migrate StatusBloc → OnlineStatusNotifier (heartbeat timer + lifecycle)
- Migrate ExtensionBloc → MitraExtensionNotifier (accept/reject + goodbye)
- Migrate ChatRequestBloc → ChatRequestNotifier (WebSocket incoming requests)
- Migrate MitraChatBloc → MitraChatNotifier (WebSocket chat + messages)
- Update router to use Riverpod auth state for redirects
- Remove all flutter_bloc usage from mitra_app screens and main.dart
- MultiBlocProvider fully removed from mitra_app

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

mitra_app/lib/features/auth/screens/login_screen.dart

@@ -1,16 +1,16 @@
 import 'package:flutter/material.dart';
-import 'package:flutter_bloc/flutter_bloc.dart';
+import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:go_router/go_router.dart';
-import '../../../core/auth/auth_bloc.dart';
+import '../../../core/auth/auth_notifier.dart';
 
-class LoginScreen extends StatefulWidget {
+class LoginScreen extends ConsumerStatefulWidget {
   const LoginScreen({super.key});
 
   @override
-  State<LoginScreen> createState() => _LoginScreenState();
+  ConsumerState<LoginScreen> createState() => _LoginScreenState();
 }
 
-class _LoginScreenState extends State<LoginScreen> {
+class _LoginScreenState extends ConsumerState<LoginScreen> {
   final _phoneController = TextEditingController();
 
   @override
@@ -21,53 +21,54 @@ class _LoginScreenState extends State<LoginScreen> {
 
   @override
   Widget build(BuildContext context) {
-    return BlocListener<AuthBloc, AuthState>(
-      listener: (context, state) {
-        if (state is AuthOtpSent) {
-          context.push('/otp', extra: _phoneController.text.trim());
-        }
-        if (state is AuthError) {
-          ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text(state.message)));
-        }
-      },
-      child: Scaffold(
-        body: SafeArea(
-          child: Padding(
-            padding: const EdgeInsets.all(24),
-            child: Column(
-              mainAxisAlignment: MainAxisAlignment.center,
-              crossAxisAlignment: CrossAxisAlignment.stretch,
-              children: [
-                const Text(
-                  'Halo Bestie Mitra',
-                  style: TextStyle(fontSize: 28, fontWeight: FontWeight.bold),
-                  textAlign: TextAlign.center,
+    final authState = ref.watch(mitraAuthProvider);
+    final isLoading = authState is AsyncLoading;
+
+    ref.listen(mitraAuthProvider, (prev, next) {
+      final data = next.valueOrNull;
+      if (data is MitraAuthOtpSentData) {
+        context.push('/otp', extra: _phoneController.text.trim());
+      }
+      if (next is AsyncError) {
+        ScaffoldMessenger.of(context).showSnackBar(SnackBar(content: Text(next.error.toString())));
+      }
+    });
+
+    return Scaffold(
+      body: SafeArea(
+        child: Padding(
+          padding: const EdgeInsets.all(24),
+          child: Column(
+            mainAxisAlignment: MainAxisAlignment.center,
+            crossAxisAlignment: CrossAxisAlignment.stretch,
+            children: [
+              const Text(
+                'Halo Bestie Mitra',
+                style: TextStyle(fontSize: 28, fontWeight: FontWeight.bold),
+                textAlign: TextAlign.center,
+              ),
+              const SizedBox(height: 48),
+              TextField(
+                controller: _phoneController,
+                decoration: const InputDecoration(
+                  labelText: 'Nomor HP',
+                  hintText: '+628xxxxxxxxxx',
+                  border: OutlineInputBorder(),
                 ),
-                const SizedBox(height: 48),
-                TextField(
-                  controller: _phoneController,
-                  decoration: const InputDecoration(
-                    labelText: 'Nomor HP',
-                    hintText: '+628xxxxxxxxxx',
-                    border: OutlineInputBorder(),
-                  ),
-                  keyboardType: TextInputType.phone,
-                ),
-                const SizedBox(height: 16),
-                BlocBuilder<AuthBloc, AuthState>(
-                  builder: (context, state) => ElevatedButton(
-                    onPressed: state is AuthLoading ? null : () {
-                      final phone = _phoneController.text.trim();
-                      if (phone.isEmpty) return;
-                      context.read<AuthBloc>().add(PhoneOtpRequested(phone));
-                    },
-                    child: state is AuthLoading
-                        ? const CircularProgressIndicator()
-                        : const Text('Kirim OTP'),
-                  ),
-                ),
-              ],
-            ),
+                keyboardType: TextInputType.phone,
+              ),
+              const SizedBox(height: 16),
+              ElevatedButton(
+                onPressed: isLoading ? null : () {
+                  final phone = _phoneController.text.trim();
+                  if (phone.isEmpty) return;
+                  ref.read(mitraAuthProvider.notifier).requestOtp(phone);
+                },
+                child: isLoading
+                    ? const CircularProgressIndicator()
+                    : const Text('Kirim OTP'),
+              ),
+            ],
           ),
         ),
       ),