Unit tests cover the token cache, the single re-exchange on a refused
token, the key's end read from a capped token, the 429 wait, the range
chunking, and every resource's mapping over made-up records shaped from
Garmin's document. The card test pins the shared anatomy, the menu and
the expiry sentences. The integration test runs the sync, the backfill,
connect and disconnect against a fake Garmin served over HTTP and the
real schema: rows per resource under GARMIN, no second row on a re-sync,
a refused key parked after one retry, a 429 that stops the run, a
history walked to its start across slices, and a purge on disconnect
that keeps the imported history.
