Add ~290 new unit tests covering utils (lru, diff, css, a11y, walk,
usage, txt-worker), services (EdgeTTSClient, transformers), and
suppress noisy console output across all test files. Rename 27
camelCase test files to dash-case for consistency.
Co-authored-by: Claude Opus 4.6 (1M context) <noreply@anthropic.com>