[Feat]: Enhance the SQL DB integration for message-only agents

[yonil7]

According to the A2A documentation here:
"Conceptually, agents operate at different levels of complexity:
Message-only Agents: Always respond with Message objects. They typically don't manage complex state or long-running executions, and use contextId to tie messages together.
..."

The current SQL DB integration only saves tasks and their related messages.
Incase the agent is a "message-only agent" (for example a chatbot that handles a conversation with the user), the messages are not saved persistently on the DB (as they are not part of a task).

[lkawka]

Hi yonil7, I understand your request but I think this isn't the responsibility of the A2A SDK. Tasks are stored because the SDK provides a basic support for task management. But messages and context in general are part of the agent execution which should be handled by the provided agent implementation (e.g., sessions in ADK). Let me know if you have any further questions.

[yonil7]

OK, understood, thanks.