Everruns 0.20.0: Register capabilities on a running runtime

Highlights

• Register capabilities on a running runtime: A host holding Arc<InProcessRuntime> can now make a capability discovered after composition resolvable without rebuilding the runtime, via register_capability/is_capability_registered. Registration stays separate from activation, and readers always see a consistent registry snapshot (#3224).
• A2A delegation is now opt-in: Outbound A2A delegation moved behind a new a2a Cargo feature, off by default, so the standard build no longer drags a second HTTP/TLS stack into consumers that only run the local runtime. Hosts that delegate to remote A2A agents enable the a2a feature explicitly (#3221).

In the changelog

• A2A delegation in the everruns crate is now an opt-in feature
• Register a capability on a running Framework runtime

Before upgrading, read the breaking changes: A2A delegation in the everruns crate is now an opt-in feature.

See the GitHub release and the full release notes for every pull request in this version.