json-rpc: Add the support for json-rpc response

[tyxia]

jso-rpc response is important for a2a, for example Task/Message Ops response

[repokitteh-read-only]

As a reminder, PRs marked as draft will not be automatically assigned reviewers,
or be handled by maintainer-oncall triage.

Please mark your PR as ready when you want it to be reviewed!

🐱

Caused by: #43516 was opened by tyxia.

see: more, trace.

[tyxia]

/retest

[botengyao]

re the description I think the agent-card can be handled by a full buffered JSON parse, since it is a well-known json .well-known/agent-card.json which is not JSON-RPC.

But the code lgtm, thanks for iterating this!

[tyxia]

Yeah that is correct. json-rpc is used for Task/Message Ops, and plain-json is used for agent card.

Thanks!