chore(sdk): add missing changelog entry

Author: cijothomas

opentelemetry-sdk/CHANGELOG.md

@@ -2,6 +2,14 @@
 
 ## vNext
 
+- Added SDK self-observability metric `otel.sdk.processor.log.processed` for
+  `BatchLogProcessor` (feature-gated behind
+  `experimental_metrics_bound_instruments`). The metric counts processed log
+  records and includes `error.type` dimensions for outcomes like
+  `queue_full` and `already_shutdown`, enabling operators to distinguish
+  successful processing from drops due to full queue or post-shutdown emits.
+  ([#3514](https://github.com/open-telemetry/opentelemetry-rust/pull/3514))
+
 ## 0.32.1
 
 Released 2026-May-23