fix: auto-fix code issues (cron)

- 修复未定义名称 (F821): 添加缺失的导入
  - ExportEntity, ExportRelation, ExportTranscript
  - WorkflowManager, PluginManager, OpsManager
  - urllib.parse
- 修复裸异常捕获: except: → except Exception:
- 删除 __pycache__ 缓存文件
- 格式化代码 (PEP8)

自动化修复: 23个问题
剩余需手动处理: 104个行长度问题 (E501)

backend/db_manager.py

@@ -334,14 +334,15 @@ class DatabaseManager:
             """INSERT INTO entity_mentions
             (id, entity_id, transcript_id, start_pos, end_pos, text_snippet, confidence)
             VALUES (?, ?, ?, ?, ?, ?, ?)""",
-            (mention.id,
-             mention.entity_id,
-             mention.transcript_id,
-             mention.start_pos,
-             mention.end_pos,
-             mention.text_snippet,
-             mention.confidence,
-             ),
+            (
+                mention.id,
+                mention.entity_id,
+                mention.transcript_id,
+                mention.start_pos,
+                mention.end_pos,
+                mention.text_snippet,
+                mention.confidence,
+            ),
         )
         conn.commit()
         conn.close()
@@ -372,12 +373,7 @@ class DatabaseManager:
             """INSERT INTO transcripts
             (id, project_id, filename, full_text, type, created_at)
             VALUES (?, ?, ?, ?, ?, ?)""",
-            (transcript_id,
-             project_id,
-             filename,
-             full_text,
-             transcript_type,
-             now),
+            (transcript_id, project_id, filename, full_text, transcript_type, now),
         )
         conn.commit()
         conn.close()