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/MULTI_AGENT_RULES.md

@@ -18,7 +18,7 @@ We clearly separate responsibilities and permissions between roles to reduce bot
 - **Ambiguity Resolution**: If a user's requirements contain ambiguous details, do not guess. Immediately ask the user for clarification (we recommend using the `/grill-me` slash command).
 
 ### 👥 Team Leaders (팀장)
-Newly spawned agents (e.g., `antigravity`, `claude`, `hermes`, `grok`, `opencode`) act as **Team Leaders** of their respective groups. They receive delegated tasks from the General Manager and manage implementation or review workflows.
+Newly spawned agents (e.g., `antigravity`, `claude`, `hermes`, `grok`, `opencode`, `codex`) act as **Team Leaders** of their respective groups. They receive delegated tasks from the General Manager and manage implementation or review workflows.
 - **Developer Team Leader (개발 팀장)**:
   - Receives tasks from the General Manager.
   - **Task Breakdown & Planning**: Thoroughly analyzes the task, breaks it down into small units, and creates a plan.