Fetching a session's track now also grabs its summary (name, activity
type, distance, duration) from the same page and stores it — sessions
the panel has actually shown replace their raw UUID with that summary,
and are kept indefinitely regardless of age. A session nobody ever
opened (no summary) is more likely test/dead data than something worth
keeping, so it's dropped automatically after 48h.
Clicking a LiveTrack session now fetches and draws its track (line +
latest position). Garmin's own API 403s any plain server-side request
(Cloudflare bot protection), so LiveTrackClient fetches the session
page instead and pulls the track out of the server-rendered data
embedded in it. The webhook now captures the session's token too,
since the id alone isn't enough to fetch anything.
A Gmail-watching Apps Script (documented in docs/deployment.adoc) posts
the session ID from each LiveTrack email to a new webhook, which stores
it in data/livetrack.json; a new sidebar panel lists what's been
received.