Add new enterprise requirement gate.
Validation:
- `cargo test -p codex-config --lib`
- `cargo test -p codex-app-server-protocol --lib`
- `cargo test -p codex-tui --lib debug_config`
- `cargo test -p codex-app-server --lib` *(fails: stack overflow in
`in_process::tests::in_process_start_initializes_and_handles_typed_v2_request`;
reproduces when run alone)*
865ca936db