fix: Fix remaining 61 ruff linting errors (SIM102, SIM117)

Fixed all remaining linting errors from the 310 total:
- SIM102: Combined nested if statements (31 errors)
  - adaptors/openai.py
  - config_extractor.py
  - codebase_scraper.py
  - doc_scraper.py
  - github_fetcher.py
  - pattern_recognizer.py
  - pdf_scraper.py
  - test_example_extractor.py

- SIM117: Combined multiple with statements (24 errors)
  - tests/test_async_scraping.py (2 errors)
  - tests/test_github_scraper.py (2 errors)
  - tests/test_guide_enhancer.py (20 errors)

- Fixed test fixture parameter (mock_config in test_c3_integration.py)

All 700+ tests passing.

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

src/skill_seekers/mcp/git_repo.py

@@ -270,7 +270,4 @@ class GitConfigRepo:
             return ":" in git_url and len(git_url.split(":")) == 2
 
         # Accept file:// URLs (for local testing)
-        if git_url.startswith("file://"):
-            return True
-
-        return False
+        return bool(git_url.startswith("file://"))