Add Codex repo-specific tracking structure

Codex/Agent/README.md

@@ -0,0 +1,20 @@
+# Agent Codex
+
+Repo: `jester/zlh-agent`
+
+Use this folder to track Agent-only work.
+
+Read in this order:
+1. `CURRENT_STATE.md`
+2. `OPEN_ITEMS.md`
+3. `DECISIONS.md`
+
+Scope:
+- game/dev container runtime behavior
+- readiness/start/restart/process supervision
+- local backup/restore behavior
+- filesystem enforcement and runtime sandboxing
+- runtime install/update/remove handling
+- code-server / dev-environment behavior inside the container
+
+Do not put API-only or Portal-only implementation details here unless they directly affect Agent behavior or integration.