## Why
The app server's device-support probe always returned `false`, preventing the bundled TUI from advertising user verification even on supported hardware.
## What changed
Use `native::device_supported` to enable the existing initialization path for in-process `codex-tui` clients that opt into `experimentalApi`. Eligible clients advertise the `userVerification` MCP extension capability and can receive verification requests.
## Testing
Add tests covering initialization eligibility, rejection of responses from non-owning connections, ownership release before disconnected RPC handlers finish draining, and cancellation of pending requests when authentication changes.
GitOrigin-RevId: cdacc026e8f830b3340f2e6f273851c4a3031a7e
