test(07-02): add failing tests for Cookie JSON parsing

- Test parse_json_cookies for Chrome Cookie Editor format
- Test domain filtering for zhihu.com
- Test empty array handling
- Test malformed JSON error handling
- Test file not found error handling

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

kb_workflow/auth/__init__.py

@@ -0,0 +1,4 @@
+"""Auth module for KB Workflow
+
+Provides authentication and cookie management functionality.
+"""