feat: add automatic mobile board layout

apps/nextjs/src/components/board/mobile/mobile-board.module.css

@@ -0,0 +1,20 @@
+.grid {
+  display: grid;
+  grid-template-columns: repeat(2, minmax(0, 1fr));
+  grid-auto-flow: row;
+  grid-auto-rows: min(calc((100vw - 42px) / 2), 12rem);
+  gap: 10px;
+  padding-bottom: 10px;
+}
+
+.item {
+  position: relative;
+  min-width: 0;
+  min-height: 0;
+}
+
+.item > :global(.grid-stack-item-content) {
+  width: 100%;
+  height: 100%;
+  overflow-y: auto;
+}