docs(changelog): add Pooling bug-fix entry for race/deadlock/leak fixes

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

Author: dkasimovskiy

CHANGELOG.md

@@ -20,6 +20,11 @@
 - Document supported Java types for Tarantool data mapping in `tuple_pojo_mapping` docs (RU/EN), including Tarantool extension types (`decimal`, `uuid`, `datetime`, `interval`, `tuple`) and related mapping notes.
 - Document Jackson MsgPack deserialization: integers, `bin`/`str` vs `byte[]`/`String`, floating-point vs `decimal`; reference `jackson-dataformat-msgpack` for defaults and type coercion.
 
+### Pooling
+
+- Fix race conditions, ABBA deadlock between `PoolEntry` and `ConnectionImpl` monitors, NPE on inline connect failure, and connection leak after a KILL/reconnect cycle in `PoolEntry` and `IProtoClientPoolImpl`.
+- Synchronize `IProtoClientPoolImpl.forEach()` on the pool lock to avoid `ConcurrentModificationException` under concurrent `setGroups()`.
+
 ### Dependencies
 - Updated dependencies: