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/entity_aligner.py

@@ -178,7 +178,10 @@ class EntityAligner:
         return best_match
 
     def _fallback_similarity_match(
-        self, entities: list[object], name: str, exclude_id: str | None = None,
+        self,
+        entities: list[object],
+        name: str,
+        exclude_id: str | None = None,
     ) -> object | None:
         """
         回退到简单的相似度匹配（不使用 embedding）
@@ -212,7 +215,10 @@ class EntityAligner:
         return None
 
     def batch_align_entities(
-        self, project_id: str, new_entities: list[dict], threshold: float | None = None,
+        self,
+        project_id: str,
+        new_entities: list[dict],
+        threshold: float | None = None,
     ) -> list[dict]:
         """
         批量对齐实体
@@ -232,7 +238,10 @@ class EntityAligner:
 
         for new_ent in new_entities:
             matched = self.find_similar_entity(
-                project_id, new_ent["name"], new_ent.get("definition", ""), threshold=threshold,
+                project_id,
+                new_ent["name"],
+                new_ent.get("definition", ""),
+                threshold=threshold,
             )
 
             result = {