feat: show lane split and retry queue in `attic status`
The status command now reads local-availability from Photos.sqlite and
the retry queue from disk, then surfaces them as two new rows:
- "Lanes" under Backup: N local / M iCloud pending, so users can see
how much of the pending work runs in the fast lane vs. the throttled
iCloud lane.
- "Retries" section: queued count, max attempts, and the date of the
oldest first failure — uses the new RetryEntry schema from beta.6.
Both rows render in rich (ANSI) and plain output.