Implements automatic detection and usage of system-installed Codex binary
with transparent fallback to embedded binary.
Changes:
- Add detectSystemCodexPath() to check for codex in PATH using `which`
- Update CodexAgentClient constructor to auto-detect system binary
- Log which binary is being used (system vs embedded) for debugging
- Preserve ability to explicitly override via codexPathOverride option
Benefits:
- No manual configuration required
- Uses latest system codex when available
- Seamless fallback to embedded binary
- Transparent to rest of codebase
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
