chore(mining-app): configure release build

- Add kDebugMode check to LoggingInterceptor to suppress logs in release
- Remove debug print statements from contribution_providers
- Add Play Core proguard rules to fix R8 missing classes error

Build command: flutter build apk --release --split-per-abi --target-platform android-arm,android-arm64
Output:
- app-arm64-v8a-release.apk: 18MB
- app-armeabi-v7a-release.apk: 16MB

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

frontend/mining-app/android/app/proguard-rules.pro

@@ -6,6 +6,10 @@
 -keep class io.flutter.**  { *; }
 -keep class io.flutter.plugins.**  { *; }
 
+# Play Core (deferred components)
+-dontwarn com.google.android.play.core.**
+-keep class com.google.android.play.core.** { *; }
+
 # 保持Gson相关
 -keepattributes Signature
 -keepattributes *Annotation*

frontend/mining-app/lib/core/network/interceptors.dart

@@ -1,4 +1,5 @@
 import 'package:dio/dio.dart';
+import 'package:flutter/foundation.dart';
 import 'package:logger/logger.dart';
 
 class LoggingInterceptor extends Interceptor {
@@ -8,19 +9,25 @@ class LoggingInterceptor extends Interceptor {
 
   @override
   void onRequest(RequestOptions options, RequestInterceptorHandler handler) {
-    _logger.d('REQUEST[${options.method}] => PATH: ${options.path}');
+    if (kDebugMode) {
+      _logger.d('REQUEST[${options.method}] => PATH: ${options.path}');
+    }
     handler.next(options);
   }
 
   @override
   void onResponse(Response response, ResponseInterceptorHandler handler) {
-    _logger.d('RESPONSE[${response.statusCode}] => PATH: ${response.requestOptions.path}');
+    if (kDebugMode) {
+      _logger.d('RESPONSE[${response.statusCode}] => PATH: ${response.requestOptions.path}');
+    }
     handler.next(response);
   }
 
   @override
   void onError(DioException err, ErrorInterceptorHandler handler) {
-    _logger.e('ERROR[${err.response?.statusCode}] => PATH: ${err.requestOptions.path}');
+    if (kDebugMode) {
+      _logger.e('ERROR[${err.response?.statusCode}] => PATH: ${err.requestOptions.path}');
+    }
     handler.next(err);
   }
 }

frontend/mining-app/lib/presentation/providers/contribution_providers.dart

@@ -69,12 +69,9 @@ final contributionRecordsProvider = FutureProvider.family<ContributionRecordsPag
   (ref, params) async {
     // 空字符串不请求
     if (params.accountSequence.isEmpty) {
-      print('[ContributionRecordsProvider] accountSequence is empty, skipping request');
       return null;
     }
 
-    print('[ContributionRecordsProvider] Fetching records for ${params.accountSequence}, page=${params.page}, pageSize=${params.pageSize}');
-
     final repository = ref.watch(contributionRepositoryProvider);
     final result = await repository.getContributionRecords(
       params.accountSequence,
@@ -82,12 +79,6 @@ final contributionRecordsProvider = FutureProvider.family<ContributionRecordsPag
       pageSize: params.pageSize,
     );
 
-    print('[ContributionRecordsProvider] Result: ${result.isRight() ? "success" : "failed"}');
-    result.fold(
-      (failure) => print('[ContributionRecordsProvider] Error: ${failure.message}'),
-      (records) => print('[ContributionRecordsProvider] Records count: ${records.data.length}, total: ${records.total}'),
-    );
-
     // 保持 provider 活跃
     ref.keepAlive();
 
@@ -119,14 +110,8 @@ final contributionStatsProvider = FutureProvider<ContributionStats?>((ref) async
   ref.onDispose(() => timer.cancel());
 
   return result.fold(
-    (failure) {
+    (failure) => null,
-      print('[ContributionStatsProvider] Error: ${failure.message}');
+    (stats) => stats,
-      return null;
-    },
-    (stats) {
-      print('[ContributionStatsProvider] Total contribution: ${stats.totalContribution}');
-      return stats;
-    },
   );
 });