Admin Run Digest Confirm

Manually trigger the Market Digest confirm phase (the API fallback).

Same code path as python -m app.cron.digest_confirm. Clears 'needs_research' stragglers the local booking-scout loop didn't reach, writing verdicts through the same state machine. Returns the run summary (rows processed, confirmed / killed) so you can smoke-test in dev/prod without waiting for the cron tick.

OFF BY DEFAULT — set USE_DIGEST_API_CONFIRM=true to arm it. Honors DIGEST_CONFIRM_TEST_PROFILE for a single-profile run and DIGEST_DRY_RUN for a write-nothing preview.