feat: update to unstable schema and metadata

[frostming]

Signed-off-by: Frost Ming me@frostming.com

Summary

This PR integrates the change of unstable schema and metadata.

the refs/main tag will be updated once the upstream release is tagged.

Related issues

Testing

Docs & screenshots

Checklist

• Conventional Commit title (e.g. feat:, fix:).
• Tests cover the change or are not required (explain above).
• Docs/examples updated when behaviour is user-facing.
• Schema regenerations (make gen-all) are called out if applicable.

[PsiACE]

My main concern now is the compatibility boundary between the stable and unstable parts of the schema, and whether we should reflect that separation explicitly in the Python SDK.

[frostming]

In fact, we have no restrictions on the protocol side; Agent and Client developers are free to define any methods they like, whether legal or illegal. And I only added a guard in the caller site(router).

[PsiACE]

Schema version 0.7.0 has just been released https://github.com/agentclientprotocol/agent-client-protocol/releases/tag/v0.7.0 . We may need to generate and debug the new schema on this PR.

[frostming]

Schema version 0.7.0 has just been released https://github.com/agentclientprotocol/agent-client-protocol/releases/tag/v0.7.0 . We may need to generate and debug the new schema on this PR.

Complete. Also added a flag to enable the use of unstable protocol(disabled by default).

[PsiACE]

LGTM, thanks