Add parallel test execution with worker pool (default: CPU count).
New --concurrency N option (--concurrency 1 for sequential).
Pre-warm shared fixtures before parallel run.
Skip snapshot update/compare for external (read-only) workspaces —
prevents accidental copying of large config dumps.
Fix normalizeUuids for cf-info/cf-validate (false→true).
Result: 283 tests, 329s→84s (4x speedup).
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>