garminconnect's own GarminConnectNotFoundError already exists
specifically for this (its docstring: "so callers can now catch a
missing resource specifically, e.g. deleting an already-deleted
workout"), raised by connectapi() for any real HTTP 404. dispatch()
now surfaces that distinction as an extra not_found: true field
alongside the existing error string, so internal/garmin/client.go
(next commit) can tell a definitive 404 apart from a transient
failure.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>