- Detect crashed rtl_433 process via poll() and clean up stale state
instead of permanently blocking restarts with 409
- Replace innerHTML+onclick preset rendering with createElement/addEventListener
to prevent XSS via crafted localStorage frequency values
- Normalize preset frequencies to toFixed(3) on save and render
- Add try/catch + shape validation to loadPresets() for corrupted localStorage
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>