Final completeness by time window: ranges keep their posting span, release_final() over blocks of done ranges

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

app/services/batch_store.ts

@@ -95,6 +95,9 @@ class BatchStore {
         .update({
           next_id: batch.next,
           headers: db.raw('headers + ?', [batch.headers]),
+          // The range's posting time span (release_final): the batches' trimmed spans, min and max (least and greatest skip nulls).
+          posted_low: db.raw('least(posted_low, to_timestamp(?::double precision / 1000))', [batch.postedLow ?? null]),
+          posted_high: db.raw('greatest(posted_high, to_timestamp(?::double precision / 1000))', [batch.postedHigh ?? null]),
           heartbeat_at: new Date(),
         })
       if (Number(moved) !== 1 && !(Array.isArray(moved) && moved.length === 1)) throw new StaleBatch(`Range ${rangeId} moved on meanwhile`)