Add extensive test coverage for the Dolt storage implementation: - dependencies_extended_test.go: Extended dependency operation tests - dolt_benchmark_test.go: Performance benchmarks for Dolt operations - history_test.go: Version history query tests - labels_test.go: Label operation tests These tests validate Dolt backend correctness and provide performance baselines for comparison with SQLite. Co-authored-by: upstream_syncer <matthew.baker@pihealth.ai> Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>