## Why
The updater bound its socket directly beneath `CODEX_HOME`, which can exceed Unix socket path limits. Bootstrap could also report success before the updater's manual-update socket was ready.
## What changed
- Reuse the control socket's protected binding and cleanup guard for the updater, with a symlink at the advertised socket path.
- Remove stale updater socket entries before startup while preserving regular files.
- Wait up to 30 seconds for supported automatic updaters to publish their socket, without connecting as a readiness probe. Report updater exit or timeout with stderr log context.
- Preserve compatibility with older updaters that lack the manual-update command.
## Testing
Add Unix integration tests for updater readiness with a long `CODEX_HOME` path and bootstrap failure when a regular file blocks the updater socket, verifying that the file is preserved and the daemon remains running.
GitOrigin-RevId: 57fdcbe4e6907ece68ba66178cf81f258527560c
Eric Traut
2f05c0a71f