v0.78.0 panics instead of graceful error when .codex/rules contains invalid Starlark

What version of Codex is running?

0.78.0

What subscription do you have?

max

Which model were you using?

_No response_

What platform is your computer?

_No response_

What issue are you seeing?

Description

Codex 0.78.0 crashes with a Rust panic when a project contains a .codex/rules file with invalid content (e.g., markdown instead of Starlark). Instead of a parse error, it panics in the system-configuration crate.

## Repro

``bash
mkdir test-project && cd test-project
mkdir .codex
echo "# some markdown content" > .codex/rules
codex
``

## Expected behavior

``
Error: Invalid Starlark syntax in .codex/rules at line 1
``
Or other helpful graceful handling

## Actual behavior

``
thread 'main' panicked at system-configuration-0.6.1/src/dynamic_store.rs:154:1:
Attempted to create a NULL object.
`
And running codex` crashes with no error messaging in the terminal

## Analysis

• 0.77.0: Works (likely doesn't read project-local .codex/ directories)
• 0.78.0: Panics
• Both versions bundle system-configuration-0.6.1

The new project-aware configuration feature in 0.78 appears to trigger sandbox/network initialization when processing .codex/rules, which hits a known upstream bug in the system-configuration crate when running under macOS Seatbelt.

## Environment

• macOS 26.2 (Darwin 25.2.0)
• Apple Silicon (arm64)
• codex-cli 0.78.0 via npm

## Workaround

Remove or fix the invalid .codex/rules file, or downgrade to 0.77.0.

What steps can reproduce the bug?

  mkdir test-project && cd test-project
  mkdir .codex
  echo "# some markdown content" > .codex/rules
  codex
  ```

### What is the expected behavior?

_No response_

### Additional information

_No response_