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-stop/scripts/stop_session.sh

@@ -1,7 +1,7 @@
 #!/usr/bin/env bash
 # stop_session.sh — multi-agent-mux-stop 의 부속 스크립트
 # Usage:
-#   bash stop_session.sh --session <name> [--agent claude|agy|hermes|grok|opencode] [--herdr-session <name>] \
+#   bash stop_session.sh --session <name> [--agent claude|agy|hermes|grok|opencode|codex] [--herdr-session <name>] \
 #       [--reason <reason>] [--purge-conversation] [--yes]
 #
 # 동작: 항상 graceful stop 입니다. send-keys 로 정상 종료를 유도하고
@@ -12,7 +12,7 @@
 #
 # 옵션:
 #   --session <name>        — 대상 세션 (필수)
-#   --agent <type>          — claude | agy | hermes | grok | opencode
+#   --agent <type>          — claude | agy | hermes | grok | opencode | codex
 #                             (권장: 항상 명시. 미지정 시 레지스트리 기록으로
 #                              해석 — agent 필드 → 세션명 접미사 → pane.cmd;
 #                              셋 다 실패하면 exit 2)
@@ -91,8 +91,8 @@ while [ $# -gt 0 ]; do
 done
 if [ -n "$AGENT" ]; then
   case "$AGENT" in
-    claude|agy|hermes|grok|opencode) ;;
-    *) echo "ERROR: invalid agent type '$AGENT'. Allowed types are: claude, agy, hermes, grok, opencode." >&2; exit 2 ;;
+    claude|agy|hermes|grok|opencode|codex) ;;
+    *) echo "ERROR: invalid agent type '$AGENT'. Allowed types are: claude, agy, hermes, grok, opencode, codex." >&2; exit 2 ;;
   esac
 fi
 [ -n "$SESSION_NAME" ] || { echo "ERROR: --session required" >&2; usage; exit 2; }
@@ -289,6 +289,8 @@ if captured and not purge:
         target['grok_session_id_own'] = captured
     elif agent == 'opencode':
         target['opencode_session_id_own'] = captured
+    elif agent == 'codex':
+        target['codex_session_id_own'] = captured
     target['resumable'] = True
 
 if purge and purge_uuid: