chore: Remove client-specific docs, fix linter errors, update documentation

- Remove SPYKE-related client documentation files
- Fix critical ruff linter errors:
  - Remove unused 'os' import in test_analyze_e2e.py
  - Remove unused 'setups' variable in test_test_example_extractor.py
  - Prefix unused output_dir parameter with underscore in codebase_scraper.py
  - Fix import sorting in test_integration.py
- Update CHANGELOG.md with comprehensive C3.9 and enhancement features
- Update CLAUDE.md with --enhance-level documentation

All critical code quality issues resolved.

tests/test_analyze_e2e.py

@@ -5,7 +5,6 @@ Tests real-world usage scenarios with actual command execution.
 """
 
 import json
-import os
 import shutil
 import subprocess
 import sys