chore(jetstream): log bulk-create record count on flush

jetstream.ts

@@ -59,7 +59,7 @@ const fireWebhooks = async (
   await dispatchAll(webhooks, payload, `${verb} ${did}`);
 };
 
-const BULK_CREATE_DEBOUNCE_MS = 3000;
+const BULK_CREATE_DEBOUNCE_MS = 15000;
 
 type BulkBuffer = {
   records: Record<string, unknown>[];
@@ -72,6 +72,7 @@ const flushBulkCreate = async (did: string): Promise<void> => {
   if (!buffer) return;
   bulkBuffers.delete(did);
   const webhooks = getWebhooksByDidAndVerb(did, "bulk-create");
+  log(`[jetstream] bulk-create ${did}: ${buffer.records.length} record(s)`);
   await dispatchAll(
     webhooks,
     { event: "bulk-create", did, records: buffer.records },