docs: extend changelog entries to cover the draining tracker / gauge

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

Author: d-cs

.changeset/mollifier-drain-batch-size.md

@@ -2,4 +2,4 @@
 "@trigger.dev/redis-worker": patch
 ---
 
-`MollifierDrainer` accepts a `drainBatchSize` option (default 1) that controls how many entries are popped per env per tick — in-flight handlers remain capped by the global `concurrency`.
+`MollifierDrainer` accepts a `drainBatchSize` option (default 1) that controls how many entries are popped per env per tick — in-flight handlers remain capped by the global `concurrency`. `MollifierBuffer` also gains `getDrainingCount()` / `listStaleDraining()`, backed by a new `mollifier:draining` ZSET maintained atomically with pop/ack/fail/requeue (observability-only).

.server-changes/mollifier-drain-batch-size.md

@@ -3,4 +3,4 @@ area: webapp
 type: improvement
 ---
 
-Wire `TRIGGER_MOLLIFIER_DRAIN_BATCH_SIZE` (default 50) so single-env bursts drain at the full `DRAIN_CONCURRENCY` budget per tick instead of one entry per tick.
+Wire `TRIGGER_MOLLIFIER_DRAIN_BATCH_SIZE` (default 50) so single-env bursts drain at the full `DRAIN_CONCURRENCY` budget per tick instead of one entry per tick. Also expose `mollifier.draining.current` ObservableGauge (polled every 15s on drainer pods) for in-flight DRAINING entries.