## What changed
- Add `EnvironmentManager::publish_ready_info` to update the selected capability
roots for an existing environment without replacing it.
- Store readiness as an atomically replaceable snapshot so repeated publications
expose the latest roots while deferred completion still controls connection
readiness.
- Validate published roots and reject updates for missing environments.
## Testing
- Cover publication, replacement, repeated and invalid updates, and interaction
with deferred environment completion.
GitOrigin-RevId: 1477f60e1319f840e6b33703ef2af052713779fd