Update: PubMed Review Streaming Tool returns json

Features

Refactor pubmed_review to return content in JSON response - Content now embedded in response instead of file writing for better integration

Testing

Add comprehensive unit tests to improve code coverage (35% → 50.5%)
Update tests for refactored pubmed_review and structure tests

Code Quality

Fix linting and type checking issues (black, ruff, mypy)
Format code with black across examples
Remove unused imports and fix import ordering
Add type annotations to mock functions

Cleanup

Remove legacy file writing mode from pubmed_review
Remove TEST_COVERAGE_STATUS.md (added to gitignore)

Test Results

118 tests passing, 21 skipped
All linters passing: black ✓, ruff ✓, mypy ✓