docs: Add comprehensive code review fixes summary

Complete documentation of all fixes applied from the critical code review:

Phase 1 (HIGH priority):
- Fix 1: Fragile YAML parsing → robust yaml library
- Fix 2: Hardcoded matching → data-driven config
- Fix 3: Test duplication → DRY principles

Phase 2 (MEDIUM priority):
- Phase 2.1: ui5-best-practices -23% (3 references)
- Phase 2.2: ui5-typescript-expert -44% (3 references)
- Phase 2.3: ui5-integration-cards -39% (3 references)

Phase 3 (MEDIUM priority):
- Added 12 test cases (+35% coverage)
- 97.8% accuracy, 21.7% negative coverage

Final metrics:
- Total context reduction: -927 lines (-36%)
- Test framework: -16% LOC
- All tests passing
- No security vulnerabilities

Document includes:
- Detailed issue descriptions
- Code before/after comparisons
- File change lists
- Complete metrics
- Testing validation
- Commit history

Author: d3xter666