Recover From Prev1

One-time, PER-PROGRAM recovery of rows lost to the non-atomic upsert (2026-06-14). Re-inserts rows that exist in the prev1 backup for the given source(s) but are missing from the live DB. Scoped to the named sources only (never touches other programs' freshly-ingested data), to current-window dates only (no reintroducing pruned past dates), and to missing IDs only via a hash anti-join (bypasses the PK index). Idempotent.

Body: {"sources": ["qantas", ...]} or {"source": "qantas"}