## What changed
- Add an explicit `registered_core` provisioning mode that registers the app package for both managed sandbox accounts and records their runner aliases. Authenticate callers against the service's package family and installed version.
- Persist runtime ownership and publish readiness only after both registrations and AppData metadata grants succeed. Prevent legacy setup or another owner from replacing registered sandbox accounts, and restrict `refresh_only` requests to an existing ready setup.
- Scope service and pipe names by package identity.
- Preserve registrations across package updates and clean them up when the owner uninstalls the app. Fence provisioning during teardown and defer package removal until native cleanup succeeds and the service exits.
## Testing
Add tests for registration opt-in, ownership and readiness checks, legacy setup isolation, metadata ACL preservation, listener shutdown handling, and the cleanup finalizer's commit barrier and UTF-8 input.
GitOrigin-RevId: 69e52f7463285b51f3bef831f071245f0eca0838
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