chore(main): release 0.8.0

[github-actions]

🤖 I have created a release beep boop

0.8.0 (2026-03-06)

⚠ BREAKING CHANGES

• remove methods with Optional params from LiveRequest.Builder
• remove deprecated methods accepting Optional params in InvocationContext
• remove deprecated BaseToolset.isToolSelected method
• remove Optional parameters from LlmResponse.Builder's methods
• remove support for legacy transferToAgent, superseded by transfer_to_agent

Features

• add callbacks functionality to the agent executor (7e8f9dc)
• add example on how to expose agent via A2A protocol (e3ea378)
• Adding a Builder for EventsCompactionConfig (05fbcfc)
• Adding a SessionKey for typeSafety (d899f6f)
• Adding plugin(Plugin... p) helper methods on App and Runner builders (dc1a192)
• implement partial event aggregation in RemoteA2AAgent (e064067)
• remove deprecated BaseToolset.isToolSelected method (d2f1145)
• remove deprecated methods accepting Optional params in InvocationContext (88153c8)
• remove methods with Optional params from LiveRequest.Builder (84c62a4)
• remove Optional parameters from LlmResponse.Builder's methods (a3ac436)

Bug Fixes

• Allow injecting ObjectMapper in FunctionTool, default to ObjectMapper (re. #473) (71b1070)
• downgrade otel.version to 1.51.0 (117fedf)
• Ensure Gemini 3.1 models have events correctly buffered (acffdb9)
• Exit from rearrangeEventsForLatestFunctionResponse if size of events is less than 2 (5bc3ef8)
• Fixed issue where events were marked empty if the first part had an empty text; now checks all parts for meaningful content (a0cba25)
• prepare JSON serialization for Jackson 2.20.2 and Spring Boot 4.0.2 upgrades (8c6591b)

Miscellaneous Chores

• revert: switch release please secret to use adk-java-releases-bot's token (7eafd1b)

Code Refactoring

• remove support for legacy transferToAgent, superseded by transfer_to_agent (c1ccb2e)

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