fix: address assistant review feedback

apps/nextjs/src/components/board/items/actions/empty-position.ts

@@ -7,7 +7,7 @@ export const getFirstEmptyPosition = (
   size: { width: number; height: number } = { width: 1, height: 1 },
 ) => {
   for (let yOffset = 0; yOffset < rowCount + 1 - size.height; yOffset++) {
-    for (let xOffset = 0; xOffset < columnCount; xOffset++) {
+    for (let xOffset = 0; xOffset <= columnCount - size.width; xOffset++) {
       const isOccupied = elements.some(
         (element) =>
           element.yOffset < yOffset + size.height &&

apps/nextjs/src/components/board/items/actions/test/empty-position.spec.ts

@@ -18,6 +18,7 @@ describe("get first empty position", () => {
       0,
     ],
     [[["a", "a", "a", "a"]], [1, 1], 0, 1],
+    [[["a", " ", " ", " "]], [4, 1], 0, 1],
     [
       [
         ["a", "a", "a", "a"],