fix: 修复AI任务生成和配置文件缺失问题

问题1：GET /api/tasks返回404错误
- 原因：缺少config.json配置文件
- 解决方案：从config.json.example复制创建config.json

问题2：'NoneType' object has no attribute 'strip'错误
- 原因：src/prompt_utils.py中AI返回的content可能为None，直接调用.strip()导致错误
- 解决方案：添加None值检查，提供更清晰的错误信息

修复内容：
- 添加config.json配置文件以支持任务管理
- 在prompt_utils.py中添加AI响应内容的空值检查
- 当AI返回空内容时提供更有意义的错误提示

🤖 Generated with [Claude Code](https://claude.ai/code)

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

config.json

@@ -0,0 +1,41 @@
+[
+  {
+    "task_name": "MacBook Air M1",
+    "enabled": true,
+    "keyword": "macbook air m1",
+    "max_pages": 5,
+    "personal_only": true,
+    "min_price": "3000",
+    "max_price": "5000",
+    "cron": "3 12 * * *",
+    "ai_prompt_base_file": "prompts/base_prompt.txt",
+    "ai_prompt_criteria_file": "prompts/macbook_criteria.txt",
+    "is_running": false
+  },
+  {
+    "task_name": "DJI Mini 3 Pro",
+    "enabled": true,
+    "keyword": "mini 3 pro",
+    "max_pages": 3,
+    "personal_only": true,
+    "ai_prompt_base_file": "prompts/base_prompt.txt",
+    "ai_prompt_criteria_file": "prompts/dji_mini3_criteria.txt",
+    "min_price": "3500",
+    "max_price": "4500",
+    "cron": "",
+    "is_running": false
+  },
+  {
+    "task_name": "婴儿车",
+    "enabled": false,
+    "keyword": "babycare 婴儿车",
+    "max_pages": 3,
+    "personal_only": true,
+    "min_price": "500",
+    "max_price": "1000",
+    "cron": "",
+    "ai_prompt_base_file": "prompts/base_prompt.txt",
+    "ai_prompt_criteria_file": "prompts/babycare_婴儿车_criteria.txt",
+    "is_running": false
+  }
+]

src/prompt_utils.py

@@ -65,6 +65,11 @@ async def generate_criteria(user_description: str, reference_file_path: str) ->
         )
         generated_text = response.choices[0].message.content
         print("AI已成功生成内容。")
+        
+        # 处理content可能为None的情况
+        if generated_text is None:
+            raise RuntimeError("AI返回的内容为空，请检查模型配置或重试。")
+        
         return generated_text.strip()
     except Exception as e:
         print(f"调用 OpenAI API 时出错: {e}")