Phase 3.1: Remove flutter_bloc + equatable, delete old bloc files

- Remove flutter_bloc and equatable dependencies from both apps
- Delete all 10 old bloc files (5 per app)
- Fix 6 remaining screens that used context.read<ApiClient>() from
  flutter_bloc → converted to ConsumerStatefulWidget/ConsumerWidget
  with ref.read(apiClientProvider)
- Both apps now use Riverpod exclusively for state management

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

mitra_app/lib/features/chat/screens/active_sessions_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/api/api_client.dart';
+import '../../../core/api/api_client_provider.dart';
 
-class ActiveSessionsScreen extends StatefulWidget {
+class ActiveSessionsScreen extends ConsumerStatefulWidget {
   const ActiveSessionsScreen({super.key});
 
   @override
-  State<ActiveSessionsScreen> createState() => _ActiveSessionsScreenState();
+  ConsumerState<ActiveSessionsScreen> createState() => _ActiveSessionsScreenState();
 }
 
-class _ActiveSessionsScreenState extends State<ActiveSessionsScreen> {
+class _ActiveSessionsScreenState extends ConsumerState<ActiveSessionsScreen> {
   List<Map<String, dynamic>> _sessions = [];
   bool _loading = true;
 
@@ -22,7 +22,7 @@ class _ActiveSessionsScreenState extends State<ActiveSessionsScreen> {
 
   Future<void> _loadSessions() async {
     try {
-      final apiClient = context.read<ApiClient>();
+      final apiClient = ref.read(apiClientProvider);
       final response = await apiClient.get('/api/mitra/chat-requests/sessions/active');
       setState(() {
         _sessions = List<Map<String, dynamic>>.from(response['data'] as List);
@@ -48,7 +48,7 @@ class _ActiveSessionsScreenState extends State<ActiveSessionsScreen> {
 
     if (confirmed == true) {
       try {
-        final apiClient = context.read<ApiClient>();
+        final apiClient = ref.read(apiClientProvider);
         await apiClient.post('/api/mitra/chat-requests/sessions/$sessionId/end');
         _loadSessions();
       } catch (_) {