chore: ruff 代码检查与修复

130 issues auto-fixed (import ordering, UP045/UP006 type annotations),
33 issues manually fixed (E712/E501/E402/E722 + N818 rename + per-file
wechat ignore for N8xx naming conventions). All 33 tests pass.

tests/test_services/test_pipeline.py

@@ -1,8 +1,10 @@
-import pytest
-from unittest.mock import AsyncMock, MagicMock, patch
 from datetime import datetime
-from app.services.pipeline import PostCrawlPipeline
+from unittest.mock import AsyncMock, patch
+
+import pytest
+
 from app.crawler.base import CrawlResult, PipelineConfig
+from app.services.pipeline import PostCrawlPipeline
 
 
 @pytest.mark.asyncio