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/scripts/orc_onboard.sh

@@ -103,7 +103,7 @@ detect_nearest_agent() {
       local base
       base="$(basename "$tok")"
       case "$base" in
-        claude|agy|hermes|grok|opencode)
+        claude|agy|hermes|grok|opencode|codex)
           match="$base"
           break
           ;;
@@ -130,6 +130,9 @@ detect_nearest_agent() {
         opencode)
           detected_id=$(echo "$cmd_line" | grep -oE '(--session|-s)[[:space:]=]+[^[:space:]]+' | head -n 1 | sed -E 's/^(--session|-s)[[:space:]=]+//' || true)
           ;;
+        codex)
+          detected_id=$(echo "$cmd_line" | grep -oE 'resume[[:space:]]+.*[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}' | grep -oE '[0-9a-fA-F]{8}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{4}-[0-9a-fA-F]{12}' | head -n 1 || true)
+          ;;
       esac
 
       if [ -n "$detected_id" ] && is_valid_id "$detected_id"; then
@@ -145,6 +148,7 @@ detect_nearest_agent() {
         hermes) env_var="${HERMES_SESSION_ID:-}" ;;
         grok) env_var="${GROK_SESSION_ID:-}" ;;
         opencode) env_var="${OPENCODE_SESSION_ID:-}" ;;
+        codex) env_var="" ;;
       esac
 
       if [ -n "$env_var" ] && is_valid_id "$env_var"; then