docs(reference): preserve local ACE command catalog

memory/reference_ace_commands.md

@@ -0,0 +1,26 @@
+---
+name: reference_ace_commands
+description: "Local ACE server command catalog and durable test-state cautions."
+tags: [ace, commands, server, testing, reference]
+---
+
+# ACE command reference
+
+The local server's complete `@acecommands` output is preserved at
+[`docs/reference/ace-commands.md`](../docs/reference/ace-commands.md).
+Use `@acehelp <command>` against the running server for exact syntax because
+the command catalog is server-version-specific.
+
+## Persistent test-state cautions
+
+- `@attackable` toggles whether monsters attack the current character. The
+  value is server-side and persists across clients, so retail reproduces the
+  same immunity. Toggle it back after tests that disable it.
+- `@god` is a persistent and potentially destructive character conversion,
+  not a temporary client diagnostic. Prefer a disposable test character and
+  use `@ungod` only with the server's documented recovery caveats.
+- `@neversaydie`, `@cloak`, `@mrt`, `@portal_bypass`, and similar toggles can
+  also survive long enough to invalidate client comparisons. When retail and
+  acdream reproduce the same symptom on the same character, audit ACE state
+  before attributing it to client code.
+- `@` and `/` are interchangeable command prefixes in AC.