feat: implement IPTV settings management with streaming and display preferences

bin/api/settings_handler.dart

@@ -0,0 +1,62 @@
+import 'dart:convert';
+import 'package:shelf/shelf.dart';
+import 'package:shelf_router/shelf_router.dart';
+import '../database/database.dart';
+import '../models/user.dart';
+
+class SettingsHandler {
+  final AppDatabase db;
+
+  SettingsHandler(this.db);
+
+  Router get router {
+    final router = Router();
+
+    // GET /api/settings
+    router.get('/', (Request req) {
+      final user = req.context['user'] as User?;
+      if (user == null) {
+        return Response.forbidden(jsonEncode({'error': 'Authentication required'}));
+      }
+
+      final settingsJson = db.getUserSettings(user.id);
+      
+      // If no settings exist, return empty object or default
+      return Response.ok(
+        settingsJson ?? '{}',
+        headers: {'content-type': 'application/json'},
+      );
+    });
+
+    // POST /api/settings
+    router.post('/', (Request req) async {
+      final user = req.context['user'] as User?;
+      if (user == null) {
+        return Response.forbidden(jsonEncode({'error': 'Authentication required'}));
+      }
+
+      try {
+        final body = await req.readAsString();
+        // Validate JSON
+        try {
+          jsonDecode(body);
+        } catch (e) {
+          return Response.badRequest(body: jsonEncode({'error': 'Invalid JSON'}));
+        }
+
+        db.updateUserSettings(user.id, body);
+
+        return Response.ok(
+          body,
+          headers: {'content-type': 'application/json'},
+        );
+      } catch (e) {
+        return Response.internalServerError(
+          body: jsonEncode({'error': 'Failed to save settings: $e'}),
+        );
+      }
+    });
+
+    return router;
+  }
+}