## What changed
- Carry a plugin's local and remote identities together from plugin loading into
`SkillMetadata`.
- Resolve remote IDs from the installed-plugin snapshot when available, falling
back to persisted install metadata only when no snapshot exists.
- Include plugin identity in skill cache keys so identity changes refresh cached
skill metadata.
## Testing
- Cover snapshot and persisted identity resolution, local marketplace isolation,
cached skill refreshes, and propagation through plugin skill snapshots.
GitOrigin-RevId: aabeeb631a43361fe817358ace7f1ea8ba5db708