feat(agent): add full codex agent support (v4.2.0)

- Implement CodexAdapter in lib_py/agents/adapters/codex.py with safe flags and TUI readiness
- Extend create_session, resume_session, stop_session, and reconcile for codex CLI
- Support codex agent delegation and loop integration across all multi-agent skills
- Add unit, component, and contract test suites for codex integration
- Verify all 462 tests passing cleanly

.agents/skills/lib_py/atomic_yaml.py

@@ -129,7 +129,7 @@ def atomic_dump_yaml_main():
             if name in old_roles and s.get('role') != old_roles[name]:
                 raise SystemExit(f"VALIDATE: role of session {name!r} cannot be modified from {old_roles[name]!r} to {s.get('role')!r}")
 
-        running_keys = ['claude_session_id_own', 'agy_conversation_id_own', 'hermes_conversation_id_own', 'grok_session_id_own', 'opencode_session_id_own']
+        running_keys = ['claude_session_id_own', 'agy_conversation_id_own', 'hermes_conversation_id_own', 'grok_session_id_own', 'opencode_session_id_own', 'codex_session_id_own']
         id_to_session = {}
         for s in d.get('herdr_sessions', []):
             if s.get('status') == 'running':