fix: restore node overflow-hidden (oversized resize handles)

Removing overflow-hidden from the BaseNode root un-clipped the NodeResizer
handles, making them huge (especially when zoomed out). Clipping was never what
made left/right connection points fail — that was backend persistence (fixed
separately) — and top/bottom handles have always worked while clipped. Restore
overflow-hidden so the resizer looks correct; side handles still work.

ha-relevant: yes

frontend/src/components/canvas/nodes/BaseNode.tsx

@@ -56,7 +56,7 @@ export function BaseNode({ id, data, selected, icon: typeIcon, width, height }:
 
   return (
     <div
-      className="relative flex flex-col rounded-lg border transition-all duration-200"
+      className="relative flex flex-col rounded-lg border transition-all duration-200 overflow-hidden"
       style={{
         background: colors.background,
         borderColor: colors.border,