Add Codex repo-specific tracking structure

Codex/Portal/README.md

@@ -0,0 +1,20 @@
+# Portal Codex
+
+Repo: `jester/zpack-portal`
+
+Use this folder to track Portal-only work.
+
+Read in this order:
+1. `CURRENT_STATE.md`
+2. `OPEN_ITEMS.md`
+3. `DECISIONS.md`
+
+Scope:
+- dashboard and control surface behavior
+- readiness / operation / maintenance UI
+- backup UI
+- billing and auth UI
+- hosted IDE entry flow from the frontend
+- SSH snippet / power-user access UX
+
+Do not put API-only or Agent-only implementation details here unless they directly affect Portal behavior or integration.