docs(useSyncRef): add jsdoc

packages/base/src/hooks/useSyncRef.ts

@@ -3,6 +3,29 @@
 import type { MutableRefObject, Ref, RefCallback } from 'react';
 import { useCallback, useRef } from 'react';
 
+/**
+ * A hook that synchronizes an external ref (callback or object) with an internal ref.
+ *
+ * @example
+ * ```tsx
+ * const MyComponent = forwardRef<HTMLDivElement, PropTypes>((props, ref) => {
+ *   const [componentRef, localRef] = useSyncRef<HTMLDivElement>(ref);
+ *
+ *   useEffect(() => {
+ *     // `localRef.current` is always the latest DOM node (or `null`)
+ *     console.log('current node:', localRef.current);
+ *   }, []);
+ *
+ *   return <div ref={componentRef}>Hello World!</div>;
+ * });
+ * ```
+ *
+ * @returns [componentRef, localRef]
+ * A tuple containing:
+ *   - `componentRef`: a stable callback ref to attach to React elements. When the node
+ *      updates, it will forward the node to the external `ref` and update the internal one.
+ *   - `localRef`: an internal, ref object that holds the latest node for synchronous reads.
+ */
 export function useSyncRef<RefType = never>(
   ref: Ref<RefType>,
 ): [RefCallback<RefType>, MutableRefObject<RefType | null>] {