fix: sandbox non-stream response not sent due to @Res() express native mode

- sandbox.controller.ts: non-stream chat path now calls res.json() instead
  of returning the value (which NestJS discards in @Res() library mode)
- ai-gateway.service.ts: 商汤科技 only registers sensenova model, no longer
  overwrites deepseek registration
- .gitignore: add .playwright-mcp/ and gitea-login.png

backend/src/modules/ai/ai-gateway.service.ts

@@ -69,17 +69,16 @@ export class AIGatewayService {
       if (!apiUrl.endsWith('/chat/completions')) {
         apiUrl = apiUrl.replace(/\/+$/, '') + '/chat/completions';
       }
-      const models = ['deepseek-v4-flash', 'sensenova-6.7-flash-lite'];
-      for (const modelName of models) {
-        this.providers.set(modelName, new OpenAICompatibleProvider(
-          process.env.SENSENOVA_API_KEY!,
-          apiUrl,
-          modelName,
-          '商汤科技',
-        ));
-        this.markAvailable(modelName);
-      }
-      this.logger.log(`商汤科技已注册: ${models.join(', ')}`);
+      // 商汤科技仅注册 sensenova 自有模型，避免覆盖硅基流动的 deepseek 注册
+      const modelName = 'sensenova-6.7-flash-lite';
+      this.providers.set(modelName, new OpenAICompatibleProvider(
+        process.env.SENSENOVA_API_KEY!,
+        apiUrl,
+        modelName,
+        '商汤科技',
+      ));
+      this.markAvailable(modelName);
+      this.logger.log(`商汤科技已注册: ${modelName}`);
     }
   }
 

backend/src/modules/sandbox/sandbox.controller.ts

@@ -35,7 +35,8 @@ export class SandboxController {
       }
       res.end();
     } else {
-      return this.sandboxService.chat(req.user.userId, body.conversationId, body.model, body.messages, body, body.images);
+      const result = await this.sandboxService.chat(req.user.userId, body.conversationId, body.model, body.messages, body, body.images);
+      res.json(result);
     }
   }