docs(cvl): disambiguating same-name user-defined types by originating contract

docs/cvl/types.md

@@ -154,6 +154,19 @@ Child.ParentFileType      invalid2; // user-defined types are not inherited
 Parent.ChildFileType      invalid3; // ChildFileType is not visible in Parent
 ```
 
+```{note}
+If two user-defined types in the {term}`scene` share the same qualified name but
+have **different** definitions — for example two vendored libraries both named
+`Math`, one declaring `enum Rounding { Floor, Ceil, Trunc, Expand }` and the other
+`enum Rounding { Down, Up, Zero }` — then `Math.Rounding` is ambiguous and is
+rejected.  (Same-named types with *identical* definitions are treated as one type
+and remain usable.)  To disambiguate, qualify the type by a contract that *imports*
+the definition you want, rather than by the duplicated declaring library: if `Vault`
+imports the first `Math`, then `Vault.Rounding` names that library's `Rounding`.
+Use a contract that imports only the one definition — a contract that imports
+*both* is itself ambiguous.
+```
+
 Additional CVL types
 --------------------