Prototype a2a card artifact type - fixes #7003

[carlesarnal]

No description provided.

[EricWittmann]

Another option for this work would be to implement the Agent Card support as a custom artifact type using the new deploy-time support we have for this.

To be clear: I'm not opposed to having A2A support baked in by default to the registry, but we no longer have to do it that way. Support can be enabled via configuration and Agent Card specific functionality can be provided via javascript.

[carlesarnal]

Another option for this work would be to implement the Agent Card support as a custom artifact type using the new deploy-time support we have for this.

To be clear: I'm not opposed to having A2A support baked in by default to the registry, but we no longer have to do it that way. Support can be enabled via configuration and Agent Card specific functionality can be provided via javascript.

Yes, I know. But since this is part of a broader plan and strategy, I think it makes more sense to have it backed with the application. Apart from that, there are a few other aspects like agent authentication that need to be taken care of, so I want to keep the code in Registry.