par2 file lists dropped once their holders are final; late candidates claimable

Most par2 sets describe readable uploads whose files are never hashed, so they
were never complete and kept forever (19 GB). Candidates added to a release
after it settled were never marked ready (93,642 since 2026-10-13); the batch
store and merge mark them now, migration 5100 repairs the waiting ones
(LOG.md 2026-10-20 (87)).

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

app/services/batch_store.ts

@@ -316,6 +316,15 @@ class BatchStore {
         .ignore()
         .returning('id')
       out.candidates += added.length
+      // Files added to a settled release (a later range of its upload): the settler made its candidates claimable
+      // already and won't again (93,642 waited since 2026-10-13; LOG.md 2026-10-20 (87)).
+      if (added.length > 0) {
+        await trx.rawQuery(
+          `UPDATE probe_candidates pc SET ready = true, unreadable = NOT r.readable FROM releases r
+           WHERE pc.id = ANY(?) AND r.id = pc.release_id AND r.settled_at IS NOT NULL`,
+          [added.map((a: { id: string | number }) => String(a.id))]
+        )
+      }
     }
 
     return out