chore: add documentation files to gitignore

Keep these files locally but don't commit:
- Test coverage and improvement docs
- Code review reports
- Retrospectives
- Implementation plans

Author: tobyhede

.gitignore

@@ -206,4 +206,11 @@ release/
 __pycache__
 
 # dbdev
-eql--*.sql
+eql--*.sql
+# Documentation files (kept locally but not committed)
+tests/sqlx/TEST_MIGRATION_COVERAGE.md
+tests/sqlx/COVERAGE_IMPROVEMENTS.md
+tests/sqlx/RETROSPECTIVE.md
+docs/retrospectives/
+CODE_REVIEW_BATCH_*.md
+docs/plans/*-complete-*.md