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

tests/test_integration.py

@@ -15,8 +15,8 @@ from pathlib import Path
 # Add parent directory to path
 sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
 
-from skill_seekers.cli.doc_scraper import DocToSkillConverter, load_config, validate_config
 from skill_seekers.cli.config_validator import ConfigValidator
+from skill_seekers.cli.doc_scraper import DocToSkillConverter, load_config, validate_config
 
 
 class TestDryRunMode(unittest.TestCase):

tests/test_test_example_extractor.py

@@ -360,9 +360,8 @@ public class GameControllerTests
         instantiations = [e for e in examples if e.category == "instantiation"]
         self.assertGreater(len(instantiations), 0)
 
-        # Check for setup extraction
-        setups = [e for e in examples if e.category == "setup"]
-        # May or may not have setups depending on extraction
+        # Setup extraction may or may not occur depending on test patterns
+        # No assertion needed as setup examples are optional
 
     def test_extract_csharp_with_mocks(self):
         """Test C# mock pattern extraction (NSubstitute)"""