add ad services and Docker configuration for web app

lib/services/adsense_service_stub.dart

@@ -0,0 +1,32 @@
+import "package:flutter/widgets.dart";
+import "ad_service.dart";
+
+/// Stub implementation for non-web platforms
+class AdSenseService implements AdService {
+  bool _isLoaded = false;
+
+  @override
+  Future<void> initialize() async {
+    // Not supported on non-web platforms
+    _isLoaded = false;
+  }
+
+  @override
+  Future<void> loadBannerAd() async {
+    // Not supported on non-web platforms
+    _isLoaded = false;
+  }
+
+  @override
+  Widget getBannerWidget() {
+    return SizedBox.shrink();
+  }
+
+  @override
+  void dispose() {
+    _isLoaded = false;
+  }
+
+  @override
+  bool get isLoaded => _isLoaded;
+}