Give runtime globals definitions, export only the declared library symbols, and fence the new libFn spellings

packages/compiler/src/frontend/lowering/surfaces.ts

@@ -2263,6 +2263,7 @@ export const AMBIENT_SURFACE_FNS: readonly AmbientSurfaceRow[] = [
       "date.nativeNewFields",
       "date.nativeNewValue",
       "date.argumentsTime",
+      "date.classOperation",
     ],
     note: "zero arguments, one milliseconds/date-string argument, or local-time year/month fields; values are the read-only TimeClip scalar slice",
   },

packages/runtime/src/scr_json.c

@@ -37,7 +37,7 @@
 
 static SCR_TL ScrDyn *scr_builtin_object_prototype;
 
-const ScrDateClassHooks *scr_date_class_hooks;
+const ScrDateClassHooks *scr_date_class_hooks = NULL;
 
 /* The checked-dynamic Error.prototype (scr_dyn_error_prototype) is not the
  * prototype of scriptc's Error instances, so a change to it would not reach