Phase 3 completed: Flutter MVP with live streaming and auto-refresh

frontend/lib/services/api_service.dart

@@ -0,0 +1,45 @@
+import 'dart:convert';
+import 'package:http/http.dart' as http;
+import '../providers/settings_provider.dart';
+
+class ApiService {
+  final SettingsProvider settings;
+  final String? token;
+
+  ApiService(this.settings, this.token);
+
+  Map<String, String> get _headers => {
+    'Content-Type': 'application/json',
+    if (token != null) 'Authorization': 'Bearer $token',
+  };
+
+  Future<http.Response> register(String username, String password) async {
+    return await http.post(
+      Uri.parse("${settings.baseUrl}/api/register"),
+      headers: _headers,
+      body: jsonEncode({"username": username, "password": password}),
+    );
+  }
+
+  Future<http.Response> login(String username, String password) async {
+    return await http.post(
+      Uri.parse("${settings.baseUrl}/api/login"),
+      headers: _headers,
+      body: jsonEncode({"username": username, "password": password}),
+    );
+  }
+
+  Future<http.Response> getMyRoom() async {
+    return await http.get(
+      Uri.parse("${settings.baseUrl}/api/room/my"),
+      headers: _headers,
+    );
+  }
+
+  Future<http.Response> getActiveRooms() async {
+    return await http.get(
+      Uri.parse("${settings.baseUrl}/api/rooms/active"),
+      headers: _headers,
+    );
+  }
+}