## What changed
- Scope remote installed-plugin and loaded-plugin snapshots to the active account, and discard in-flight loads when the account changes.
- Serialize bundle reconciliation with direct installs and uninstalls, and use cache generations to prevent stale refreshes from overwriting newer state.
- Validate the complete installed-plugin snapshot before downloading bundles or removing stale cache entries, while retaining valid installed metadata when materialization fails.
## Testing
- Cover account changes during plugin loading, incomplete snapshots, refresh/reconciliation races, and reconciliation cancellation recovery.
GitOrigin-RevId: 694c25577b420b93dacc6c65e3c0ecb7b8cc64c3
e6a3877e95