feat(app): finalize ad gated flows and weather

- add AppLogger and replace scattered print logging\n- implement ad-gated recommendation flow with reminder handling and calendar link\n- complete Bluetooth share pipeline with ad gate and merge\n- integrate KMA weather API with caching and dart-define decoding\n- add NaverUrlProcessor refactor and restore restaurant repository tests

lib/core/utils/app_logger.dart

@@ -0,0 +1,28 @@
+import 'package:flutter/foundation.dart';
+
+/// 앱 전역에서 사용하는 로거.
+/// debugPrint를 감싸 경고 없이 로그를 남기며, debug 레벨은 디버그 모드에서만 출력합니다.
+class AppLogger {
+  AppLogger._();
+
+  static void debug(String message) {
+    if (kDebugMode) {
+      debugPrint(message);
+    }
+  }
+
+  static void info(String message) {
+    debugPrint(message);
+  }
+
+  static void error(String message, {Object? error, StackTrace? stackTrace}) {
+    final buffer = StringBuffer(message);
+    if (error != null) {
+      buffer.write(' | error: $error');
+    }
+    if (stackTrace != null) {
+      buffer.write('\n$stackTrace');
+    }
+    debugPrint(buffer.toString());
+  }
+}