chore: polish nip-22 changeset note

Author: Priyanshubhartistm

.changeset/nip-22-created-at-limits-coverage.md

@@ -0,0 +1,7 @@
+---
+"nostream": patch
+---
+
+Improve NIP-22 `created_at` limit handling coverage and boundary reliability.
+
+This adds integration coverage for accepted and rejected events across configured positive and negative `created_at` deltas, and keeps rejection semantics consistent (`rejected`) for out-of-range timestamps.