fix: preserve narrow board interactions

apps/nextjs/src/components/board/layout/README.md

@@ -5,7 +5,7 @@ The board uses fixed logical units:
 - one `1 × 1` item is exactly `200 × 200` logical pixels;
 - the gap is always `24` logical pixels, giving a `224` pixel track pitch;
 - multi-cell items include the gaps between their cells (`2 × 1` is `424 × 200`);
-- the canvas is transformed once with one uniform scale derived from its available width.
+- the canvas is zoomed once with one uniform scale derived from its available width.
 
 Items keep the same logical dimensions at every viewport. The viewport reserves
 the painted size while the inner canvas remains at its logical dimensions, so a

apps/nextjs/src/components/board/sections/grid/grid-editor.css

@@ -182,7 +182,7 @@ body[data-board-grid-interacting="resize"] .board-grid-entry[data-dnd-active="tr
 .board-grid-resize-handle[data-grid-resize-handle="s"] {
   right: 44px;
   left: 44px;
-  height: 32px;
+  height: max(32px, calc(25px * var(--board-canvas-inverse-scale, 1)));
   cursor: ns-resize;
 }
 
@@ -198,7 +198,7 @@ body[data-board-grid-interacting="resize"] .board-grid-entry[data-dnd-active="tr
 .board-grid-resize-handle[data-grid-resize-handle="w"] {
   top: 44px;
   bottom: 44px;
-  width: 32px;
+  width: max(32px, calc(25px * var(--board-canvas-inverse-scale, 1)));
   cursor: ew-resize;
 }
 
@@ -221,8 +221,8 @@ body[data-board-grid-interacting="resize"] .board-grid-entry[data-dnd-active="tr
 .board-grid-resize-handle[data-grid-resize-handle="sw"],
 .board-grid-resize-handle[data-grid-resize-handle="nw"] {
   z-index: 9;
-  width: 44px;
-  height: 44px;
+  width: max(44px, calc(25px * var(--board-canvas-inverse-scale, 1)));
+  height: max(44px, calc(25px * var(--board-canvas-inverse-scale, 1)));
 }
 
 .board-grid-resize-handle[data-grid-resize-handle="ne"] {