chore(main): release 0.4.0

Author: a2a-bot

CHANGELOG.md

@@ -1,5 +1,12 @@
 # Changelog
 
+## [0.4.0](https://github.com/a2aproject/a2a-python/compare/v0.3.16...v0.4.0) (2025-11-24)
+
+
+### Features
+
+* **client:** allow specifying `history_length` via call-site `MessageSendConfiguration` in `BaseClient.send_message` ([#500](https://github.com/a2aproject/a2a-python/issues/500)) ([53bbf7a](https://github.com/a2aproject/a2a-python/commit/53bbf7ae3ad58fb0c10b14da05cf07c0a7bd9651))
+
 ## [0.3.16](https://github.com/a2aproject/a2a-python/compare/v0.3.15...v0.3.16) (2025-11-21)