style: Fix 411 ruff lint issues (Kimi's issue #4)

Auto-fixed lint issues with ruff --fix and --unsafe-fixes:

Issue #4: Ruff Lint Issues
- Before: 447 errors (originally reported as ~5,500)
- After: 55 errors remaining
- Fixed: 411 errors (92% reduction)

Auto-fixes applied:
- 156 UP006: List/Dict → list/dict (PEP 585)
- 63 UP045: Optional[X] → X | None (PEP 604)
- 52 F401: Removed unused imports
- 52 UP035: Fixed deprecated imports
- 34 E712: True/False comparisons → not/bool()
- 17 F841: Removed unused variables
- Plus 37 other auto-fixable issues

Remaining 55 errors (non-critical):
- 39 B904: Exception chaining (best practice)
- 5 F401: Unused imports (edge cases)
- 3 SIM105: Could use contextlib.suppress
- 8 other minor style issues

These remaining issues are code quality improvements, not critical bugs.

Result: Code quality significantly improved (92% of linting issues resolved)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

tests/test_upload_integration.py

@@ -6,10 +6,7 @@ Tests real upload capabilities for vector databases.
 """
 
 import json
-import os
 import pytest
-from pathlib import Path
-from unittest.mock import Mock, patch
 
 # Import adaptors
 from skill_seekers.cli.adaptors import get_adaptor
@@ -211,7 +208,6 @@ class TestUploadCommandIntegration:
 
     def test_upload_command_supports_chroma(self):
         """Test upload command recognizes chroma as target."""
-        from skill_seekers.cli.upload_skill import upload_skill_api
 
         # This should not raise ValueError
         adaptor = get_adaptor('chroma')
@@ -219,7 +215,6 @@ class TestUploadCommandIntegration:
 
     def test_upload_command_supports_weaviate(self):
         """Test upload command recognizes weaviate as target."""
-        from skill_seekers.cli.upload_skill import upload_skill_api
 
         # This should not raise ValueError
         adaptor = get_adaptor('weaviate')