## Why
Allow remote exec-server registration to use credentials independently of Codex login while retaining the usual local configuration and plugins.
## What changed
- Add `--registration-bearer-stdin` to read one newline-terminated bearer and use it for remote registration.
- Validate the bearer, require HTTPS or HTTP loopback for the registry, and disable process dumpability on Linux before reading the credential.
- Document the option and its distinction from rotating credentials via `--executor-credential-stdin`.
## Testing
Add integration coverage for registration with the supplied bearer across desktop sign-in states, rejection of non-loopback HTTP registries, and restricted process environment access on Linux. Update CLI help snapshots.
GitOrigin-RevId: da99492270c5dc6bb5e0cac41947e9c999a72b75
## What changed
Extract executor startup into `codex-exec-server-cli`, shared by `codex exec-server` and the new standalone binary. Preserve executor arguments, authentication, configuration overrides, and sandbox helper dispatch across both entry points.
Build the standalone binary with `cargo build -p codex-exec-server-cli --bin codex-exec-server` and run it with `codex-exec-server --listen stdio`.
## Testing
Add standalone CLI parsing and help coverage, plus an integration test for version reporting, stdio initialization, filesystem reads, process execution, and sandbox helper re-execution when supported.
GitOrigin-RevId: ab3a81c6b91b6f45e4d72d8add2e01af8372e97f
Anton Panasenko