The bot's own importer requires an empty destination, but the bot rebuilds part of its state from Discord on
every start, so after the backend switch neither side is a superset. This merges them: log tables append on a
natural key, and the profile/state tables resolve column by column with one explicit rule per column, so the
original joined_at, first_seen_at, rank started_at and tracking start survive a rebuild that stamped today,
while current rank, presence and latest activity stay fresh.
One transaction, idempotent, and it stops rather than guessing when a column has no rule or a table is absent
from the destination. Tested against a fixture built from the real 1041-row file plus a simulated rebuild:
history restored, fresh values kept, 30 membership events (29 historical + tonight's), re-run a no-op, and
both guards verified. A KeyError on insert-only tables during the second run was found and fixed that way.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
