chore: 联网测试密钥改从环境变量读取

live_endpoint_test.dart 里硬编码了一个真实 API key。改为读取
KOUYU_AI_API_KEY（可选 KOUYU_AI_BASE_URL、KOUYU_AI_MODEL），未设置时
整组测试跳过，不再把缺少凭据的联网测试当成通过。

注意：旧 key 仍留在提交历史中，需要在服务端作废并重新签发。

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

kouyu_english/test/live_endpoint_test.dart

@@ -11,56 +11,74 @@ class RealHttpOverrides extends HttpOverrides {
   }
 }
 
+/// 读取联网测试用的配置。密钥只来自环境变量，不写进仓库。
+///
+/// 运行方式：
+///   KOUYU_AI_API_KEY=sk-xxx flutter test test/live_endpoint_test.dart
+/// 可选：KOUYU_AI_BASE_URL（默认 https://codex.slcydia.fun）、KOUYU_AI_MODEL。
+/// 未设置密钥时整组测试自动跳过，不会误报成功。
+String? _env(String name) {
+  final value = Platform.environment[name];
+  return (value == null || value.trim().isEmpty) ? null : value.trim();
+}
+
 void main() {
   TestWidgetsFlutterBinding.ensureInitialized();
   HttpOverrides.global = RealHttpOverrides();
-  const testKey = '***REMOVED***';
+
-  AiService.instance.setFallbackApiKey(testKey);
+  final apiKey = _env('KOUYU_AI_API_KEY');
+  final baseUrl = _env('KOUYU_AI_BASE_URL') ?? 'https://codex.slcydia.fun';
+  final model = _env('KOUYU_AI_MODEL') ?? 'gemini-3.7-flash-high';
+  final skipReason = apiKey == null
+      ? '未设置 KOUYU_AI_API_KEY，跳过联网测试。'
+      : null;
+  if (apiKey != null) {
+    AiService.instance.setFallbackApiKey(apiKey);
+  }
 
   test('Live test: /v1/responses endpoint testConnection', () async {
     try {
       final resResponses = await AiService.instance.testConnection(
         provider: AiProviderType.compatible,
-        endpoint: 'https://codex.slcydia.fun/v1/responses',
+        endpoint: '$baseUrl/v1/responses',
-        model: 'gemini-3.7-flash-high',
+        model: model,
-        explicitApiKey: testKey,
+        explicitApiKey: apiKey,
       );
       print('Responses API result: ok=${resResponses.ok}, msg=${resResponses.message}');
     } catch (e) {
       print('Network test skipped: $e');
     }
-  });
+  }, skip: skipReason);
 
   test('Live test: /v1 (Chat Completions) endpoint testConnection', () async {
     try {
       final resChat = await AiService.instance.testConnection(
         provider: AiProviderType.compatible,
-        endpoint: 'https://codex.slcydia.fun/v1',
+        endpoint: '$baseUrl/v1',
-        model: 'gemini-3.7-flash-high',
+        model: model,
-        explicitApiKey: testKey,
+        explicitApiKey: apiKey,
       );
       print('Chat Completions API result: ok=${resChat.ok}, msg=${resChat.message}');
     } catch (e) {
       print('Network test skipped: $e');
     }
-  });
+  }, skip: skipReason);
 
   test('Live test: /v1/responses dialogueReply', timeout: const Timeout(Duration(seconds: 60)), () async {
-
     try {
       final reply = await AiService.instance.dialogueReply(
         provider: AiProviderType.compatible,
-        endpoint: 'https://codex.slcydia.fun/v1/responses',
+        endpoint: '$baseUrl/v1/responses',
-        model: 'gemini-3.7-flash-high',
+        model: model,
         history: [
           {'role': 'user', 'content': 'Hello, my name is Alex.'}
         ],
         aiGoal: 'Greet the learner and ask their name',
         learnerTask: 'say their own name',
       );
-      print('Dialogue reply from /v1/responses: reply="${reply?.reply}", slots=${reply?.slots}, suggestsComplete=${reply?.suggestsComplete}');
+      print('Dialogue reply from /v1/responses: reply="${reply?.reply}", translation="${reply?.translation}", feedback="${reply?.feedback}"');
     } catch (e) {
       print('Network test skipped: $e');
     }
-  });
+  }, skip: skipReason);
 }