## Why
Passing extra descriptors to a PTY previously selected behavior intended for inherited escalation sockets: no EOF on stdin close, different signal exit statuses, and no default `SHELL`. Launch attachments need ordinary PTY behavior and must survive execution even when marked `FD_CLOEXEC`.
## What changed
- Add `ChildFds::Attached` alongside `ChildFds::Inherited` to distinguish launch attachments from legacy inherited descriptors.
- Preserve ordinary EOF, default `SHELL`, and signal exit status behavior for PTY attachments.
- Allow explicitly supplied close-on-exec descriptors through pipe and PTY launches without changing the parent's descriptor flags, using child-side flag updates and macOS spawn inheritance actions.
- Update existing callers to use `ChildFds::Inherited`.
## Testing
Add Unix coverage for attachment accessibility, unchanged parent descriptor flags, default `SHELL`, and signal exit statuses. Extend the PTY stdin-draining test to cover attachments and EOF delivery.
GitOrigin-RevId: 864aedc6c5717d8b43c9d71057c9f54409834509
## Why
Sandboxed commands inherit the user's controlling terminal. Without an explicit
restriction, a child can use `TIOCSTI` to queue input for the unsandboxed shell
that resumes after Codex exits.
## What changed
Append a `file-ioctl` denial for `TIOCSTI` after the shared Seatbelt policy
allowances used by `codex sandbox`.
## Testing
Add a macOS PTY integration test that first proves terminal input injection
works without the sandbox, then verifies Seatbelt rejects it with `EPERM`.
GitOrigin-RevId: 5a8b0a5b4fd980cc406ad184d04ceae9b0ea90e4
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