ludic.ui: props kept an instance, a call's arguments a depth, a loop's index shared, an absent attribute's text without a Value; runtime Value.clear - benchmark 36 -> 20 KB a frame

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

runtime/native/namespaces.ludic

@@ -479,6 +479,7 @@ namespace Value {
   alias as_float(value) = value_as_float
   alias as_str(value) = value_as_str
   alias free(value) = value_free
+  alias clear(value) = value_clear
 }
 namespace Json {
   alias encode(value) = json_encode