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-orc-onboard/SKILL.md

@@ -1,14 +1,14 @@
 ---
 name: multi-agent-mux-orc-onboard
 description: "Register current or specified orchestrator session UUID into agent-sessions.yaml orchestrator_uuids list to prevent sub-agent discovery capture."
-version: 4.1.3
+version: 4.2.0
 author: godopu
 license: MIT
 platforms: [linux, macos]
 environments: [terminal, herdr]
 metadata:
   hermes:
-    tags: [agent, herdr, claude, antigravity, agy, hermes, grok, opencode, orchestrator, onboard, isolation]
+    tags: [agent, herdr, claude, antigravity, agy, hermes, grok, opencode, codex, orchestrator, onboard, isolation]
     related_skills: [multi-agent-mux-create, multi-agent-mux-resume, multi-agent-mux-monitor]
     prereq_skills: [multi-agent-mux-create]
 ---
@@ -32,13 +32,14 @@ Registers an orchestrator session UUID into the `orchestrator_uuids` list of `.m
 
 ## Auto-Detection Hierarchy (Rev.2)
 
-When `--uuid` is omitted, `orc_onboard.sh` inspects the process ancestry tree of the nearest agent ancestor (`claude`, `agy`, `hermes`, `grok`, `opencode`) in the following order:
+When `--uuid` is omitted, `orc_onboard.sh` inspects the process ancestry tree of the nearest agent ancestor (`claude`, `agy`, `hermes`, `grok`, `opencode`, `codex`) in the following order:
 
 1. **CLI `argv`**:
    - `claude -r <uuid>` / `claude --session-id <uuid>`
    - `agy --conversation <uuid>`
    - `grok --session-id <uuid>` / `grok --resume <uuid>`
    - `opencode --session <uuid>`
+   - `codex resume <uuid>`
 2. **Family-Matched Environment Variables**:
    - `claude` → `CLAUDE_CODE_SESSION_ID`
    - `agy` → `ANTIGRAVITY_CONVERSATION_ID`