refactor entire frontend

frontend/lib/chat_list_screen.dart

@@ -0,0 +1,64 @@
+import 'package:flutter/material.dart';
+import 'backend.dart';
+import 'chat_screen.dart';
+
+class ChatEntry {
+  final int id;
+  final String name;
+
+  ChatEntry({required this.id, required this.name});
+}
+
+class ChatListScreen extends StatelessWidget {
+  const ChatListScreen({super.key});
+
+  static Future<List<ChatEntry>> getChats() async {
+    final response = await Backend.sendAction("get-chats", {});
+    List<dynamic> chatObjects = response['chats'];
+    List<ChatEntry> chats = chatObjects
+        .map((msg) => ChatEntry(
+              id: msg['id'],
+              name: msg['name']?.isNotEmpty == true ? msg['name'] : '[Chat ${msg['id']}]',
+            ))
+        .toList();
+    return chats;
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(title: const Text('Chats')),
+      body: FutureBuilder<List<ChatEntry>>(
+        future: getChats(),
+        builder: (context, snapshot) {
+          if (snapshot.connectionState == ConnectionState.waiting) {
+            return const Center(child: CircularProgressIndicator());
+          } else if (snapshot.hasError) {
+            return Center(child: Text('Error: ${snapshot.error}'));
+          } else if (!snapshot.hasData || snapshot.data!.isEmpty) {
+            return const Center(child: Text('No chats available.'));
+          } else {
+            final chats = snapshot.data!;
+            return ListView.builder(
+              itemCount: chats.length,
+              itemBuilder: (context, index) {
+                final chat = chats[index];
+                return ListTile(
+                  title: Text(chat.name),
+                  onTap: () {
+                    Navigator.push(
+                      context,
+                      MaterialPageRoute(
+                        builder: (context) => ChatScreen(chatId: chat.id),
+                      ),
+                    );
+                  },
+                );
+              },
+            );
+          }
+        },
+      ),
+    );
+  }
+}