feat(ui): min(), max() and clamp(); insets as percentages of the containing block

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

packages/ludic.ui/node_more.ludic

@@ -22,6 +22,10 @@ export property UiNodeX {
   fit_min: float = 0.0          # text-fit: shrink MIN - the smallest a line is shrunk to fit its box
   lh_kind: int = 0              # line-height: 0 normal, 1 a multiple of the font size, 2 px
   lh_v: float = 0.0
+  ip_t: float = 0.0             # an inset's percentage of its containing block (top right bottom left)
+  ip_r: float = 0.0
+  ip_b: float = 0.0
+  ip_l: float = 0.0
 }
 function nx(n: UiNode) -> UiNodeX {
   if n.ex == null { n.ex = new UiNodeX }