Single-file Web Serial app for GitHub Pages. Connects to the device
over USB CDC, auto-detects <?xml…</gpx> frame from the Export GPX
action, and offers the file as a browser download with an editable
filename (defaults to trail_YYYY-MM-DD.gpx). Resets automatically
after download so back-to-back exports work without reconnecting.
Requires Chrome/Edge (Web Serial API). Enable GitHub Pages from the
repo settings pointing at the branch root or docs/ as needed.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
