fix: auto-fix code issues (cron)

- 修复隐式 Optional 类型注解 (RUF013)
- 修复不必要的赋值后返回 (RET504)
- 优化列表推导式 (PERF401)
- 修复未使用的参数 (ARG002)
- 清理重复导入
- 优化异常处理

backend/image_processor.py

@@ -96,7 +96,7 @@ class ImageProcessor:
         "other": "其他",
     }
 
-    def __init__(self, temp_dir: str = None) -> None:
+    def __init__(self, temp_dir: str | None = None) -> None:
         """
         初始化图片处理器
 
@@ -106,7 +106,7 @@ class ImageProcessor:
         self.temp_dir = temp_dir or os.path.join(os.getcwd(), "temp", "images")
         os.makedirs(self.temp_dir, exist_ok=True)
 
-    def preprocess_image(self, image, image_type: str = None) -> None:
+    def preprocess_image(self, image, image_type: str | None = None) -> None:
         """
         预处理图片以提高OCR质量
 
@@ -328,7 +328,10 @@ class ImageProcessor:
         return unique_entities
 
     def generate_description(
-        self, image_type: str, ocr_text: str, entities: list[ImageEntity],
+        self,
+        image_type: str,
+        ocr_text: str,
+        entities: list[ImageEntity],
     ) -> str:
         """
         生成图片描述
@@ -361,8 +364,8 @@ class ImageProcessor:
     def process_image(
         self,
         image_data: bytes,
-        filename: str = None,
-        image_id: str = None,
+        filename: str | None = None,
+        image_id: str | None = None,
         detect_type: bool = True,
     ) -> ImageProcessingResult:
         """
@@ -487,7 +490,9 @@ class ImageProcessor:
         return relations
 
     def process_batch(
-        self, images_data: list[tuple[bytes, str]], project_id: str = None,
+        self,
+        images_data: list[tuple[bytes, str]],
+        project_id: str | None = None,
     ) -> BatchProcessingResult:
         """
         批量处理图片
@@ -561,7 +566,7 @@ class ImageProcessor:
 _image_processor = None
 
 
-def get_image_processor(temp_dir: str = None) -> ImageProcessor:
+def get_image_processor(temp_dir: str | None = None) -> ImageProcessor:
     """获取图片处理器单例"""
     global _image_processor
     if _image_processor is None: