feat: Add API integration tests for summarize module

- Add comprehensive Claude API integration tests (9 new tests)
- Test real API calls for documentation generation
- Test multiple scenarios: single file, multiple files, breaking changes
- Test YAML extraction, prompt building, and markdown generation
- Add pytest markers for API tests (skipped by default)
- Tests run with: pytest -m api

Coverage improvements:
- Summarize module: 12% → 93%
- Overall coverage: 59% → 65%
- All 105 tests passing (96 regular + 9 API)

API tests are marked with @pytest.mark.api and automatically skip
if ANTHROPIC_API_KEY is not set. This prevents accidental API costs
during CI/CD while allowing optional real API validation.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <[email protected]>

Author: GeneAI

pyproject.toml

@@ -129,3 +129,7 @@ python_files = "test_*.py"
 python_classes = "Test*"
 python_functions = "test_*"
 addopts = "-v --cov=memdocs --cov-report=term-missing --cov-report=html"
+markers = [
+    "slow: marks tests as slow (e.g., integration tests with real embeddings)",
+    "api: marks tests that make real API calls (skipped by default, run with: pytest -m api)",
+]