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/multi-agent-mux-delegate-job/SKILL.md

@@ -1,7 +1,7 @@
 ---
 name: multi-agent-mux-delegate-job
 description: "Delegate a unit of work to any autonomous agent (claude-code, hermes, agy, grok-build, codex, or a human) and observe it asynchronously over an MQTT event channel. Supported roles include orchestrator, worker, and reviewer."
-version: 4.1.3
+version: 4.2.0
 author: godopu
 license: MIT
 platforms: [linux, macos, windows]