## Why
A pending remote control enrollment could prevent the app server from exiting
after stdio EOF, leaving resources such as thread writers held by the process.
## What changed
- Give remote control its own child shutdown token and cancel it before draining
RPCs when the stdio connection closes.
- Interrupt enrollment requests that require network access after shutdown has
begun, while still allowing in-memory or persisted enrollments to be enabled
and durably saved.
## Testing
- Cover stdio shutdown during a blocked enrollment and verify that another app
server can acquire the released thread writer.
- Cover durable enablement after shutdown with in-memory, persisted, and missing
enrollments.
GitOrigin-RevId: ef9ab49672f273a4cf8257188454a154c03088bd
ningyi-oai
ea2046f36d