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>

packages/ludic.ui/instance.ludic

@@ -5,6 +5,7 @@ property UiInst {
   cls: UiClass = null
   ptr: pointer = null
   seen: int = 0
+  props: Val = null             # its props, filled again each frame into the same object
 }
 function in_get(ui_st: mut UiState, key: string, k: UiClass) -> UiInst {
   for i in 0 .. len(ui_st.in_list) {