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-resume/SKILL.md

@@ -1,7 +1,7 @@
 ---
 name: multi-agent-mux-resume
 description: "Resume an existing agent (claude, antigravity/agy) conversation by UUID into a herdr session. Reads .mam/agent-sessions.yaml for the saved session/conversation id, spawns (or reuses) a herdr session of the matching name, and runs `claude -r <id>` or `agy --conversation <id>` inside. Use when you want to reattach to a previous session's context, or revive a session whose herdr died but the agent's conversation is still on disk."
-version: 4.1.3
+version: 4.2.0
 author: godopu
 license: MIT
 platforms: [linux, macos]
@@ -49,16 +49,16 @@ ideal resume path:
 
 `agent-sessions.yaml` and on-disk discovery are used to resolve the UUID in this order:
 
-1. **`herdr_sessions[]` row's per-row own id** (`claude_session_id_own` / `agy_conversation_id_own` / `hermes_conversation_id_own` / `grok_session_id_own` / `opencode_session_id_own`) — explicitly saved by `multi-agent-mux-stop` right before teardown (tier-1, race-free).
+1. **`herdr_sessions[]` row's per-row own id** (`claude_session_id_own` / `agy_conversation_id_own` / `hermes_conversation_id_own` / `grok_session_id_own` / `opencode_session_id_own` / `codex_session_id_own`) — explicitly saved by `multi-agent-mux-stop` right before teardown (tier-1, race-free).
 2. **Workspace-scoped on-disk scan** (adapter `discover()`)
 
-If both are empty → for Class A agents (`agy`, `hermes`, `opencode`), `resume_session.sh` automatically falls back to `FRESH_SPAWN=1` (`spawn-spec`). For Class B agents (`claude`, `grok`), fall back to `multi-agent-mux-create`.
+If both are empty → for Class A agents (`agy`, `hermes`, `opencode`, `codex`), `resume_session.sh` automatically falls back to `FRESH_SPAWN=1` (`spawn-spec`). For Class B agents (`claude`, `grok`), fall back to `multi-agent-mux-create`.
 
 ## Workflow
 
 ```bash
 WORKSPACE=/path/to/project
-AGENT=claude  # claude | agy | hermes | grok | opencode — pass it explicitly
+AGENT=claude  # claude | agy | hermes | grok | opencode | codex — pass it explicitly
 SESSION_NAME=<workspace>-creator-<agent>  # same convention as multi-agent-mux-create
 
 # Resolve the isolated herdr server name & load common utils
@@ -70,7 +70,7 @@ UUID=$(bash .agents/skills/multi-agent-mux-resume/scripts/resolve_session_id.sh
 
 if [ -z "$UUID" ]; then
   case "$AGENT" in
-    agy|hermes|opencode)
+    agy|hermes|opencode|codex)
       : # resume_session.sh handles fresh-spawn fallback automatically (FRESH_SPAWN=1)
       ;;
     *)
@@ -97,6 +97,7 @@ case "$AGENT" in
   hermes)   CMD_FULL="hermes --resume $UUID --no-restore-cwd --yolo --accept-hooks" ;;
   grok)     CMD_FULL="grok --resume $UUID --permission-mode bypassPermissions" ;;
   opencode) CMD_FULL="opencode --session $UUID --auto --agent build" ;;
+  codex)    CMD_FULL="codex resume --dangerously-bypass-approvals-and-sandbox $UUID" ;;
 esac
 
 # 4. Spawn new herdr session + run agent with the saved id
@@ -107,7 +108,7 @@ case "$AGENT" in
     # auto-handle trust / bypass dialogs
     handle_startup_dialogs "$SESSION_NAME" 20
     ;;
-  agy|hermes|grok|opencode)
+  agy|hermes|grok|opencode|codex)
     eval "herdr new-session -d -s \"$SESSION_NAME\" -x 140 -y 40 -c \"$WORKSPACE\" \"$CMD_FULL\""
     ;;
 esac