feat(Board): add keyboard and swipe focal cycling

src/widgets/Board/lib/cycleGestures/cycleGestures.ts

@@ -0,0 +1,18 @@
+/**
+ * Maps a horizontal swipe delta to a cycle direction. A leftward swipe (negative
+ * dx) advances to the next pairing (+1); a rightward swipe (positive dx) goes to
+ * the previous (-1). Movement below the threshold is ignored (0).
+ *
+ * @param dx - Horizontal travel in px (end minus start).
+ * @param threshold - Minimum absolute travel in px to count as a swipe.
+ * @returns +1 (next), -1 (previous), or 0 (no cycle).
+ */
+export function swipeDirection(dx: number, threshold: number): -1 | 0 | 1 {
+    if (dx <= -threshold) {
+        return 1;
+    }
+    if (dx >= threshold) {
+        return -1;
+    }
+    return 0;
+}