refactor(10.2-01): nest framework packages under modules

- Move remaining beach packages and embedded admin assets\n- Rewrite framework, example, build, and gate paths

modules/cabana/admin_paths_test.go

@@ -0,0 +1,7 @@
+package cabana
+
+// adminAPI composes a full admin API path under the default prefix, so tests
+// follow the backend.uri scheme (D-03) instead of hardcoding it.
+func adminAPI(rel string) string {
+	return DefaultAdminPrefix + adminAPIVersion + rel
+}