Two fixes found during post-refactor audit:
1. upload_tracker: remove COUNT(*) guard from _maybe_migrate. The guard
blocked re-migration when a previous run successfully committed both
JSON files but a PermissionError on the second rename() left it on
disk. On the next startup COUNT > 0 → early return → rejected IDs
permanently unimported. INSERT OR IGNORE is idempotent so re-running
migration is always safe; guard not needed.
Also wrap each rename() in its own try/except so a failure on one
file is logged and does not propagate uncaught.
2. reconcile: break early when new_count > target is detected in the
poll loop. Previously the loop ran all four delay intervals (1+2+4+8s)
before the post-loop > target branch fired, wasting up to 15 seconds
when a concurrent external upload was visible on the first poll.
flan
043ebf85d7