Add JSDoc documentation to enqueueTask function

Added comprehensive JSDoc comments to the enqueueTask function to document:
- The purpose of the function
- Behavior differences between Node.js and browser environments
- Parameter and return type information

This improves code documentation and developer experience.

Author: bodhisilberling-2027

packages/shared/enqueueTask.js

@@ -10,6 +10,16 @@
 let didWarnAboutMessageChannel = false;
 let enqueueTaskImpl = null;
 
+/**
+ * Enqueues a task to be executed asynchronously.
+ * 
+ * In Node.js environments, this uses `setImmediate` to bypass fake timers.
+ * In browser environments, this uses `MessageChannel` to ensure the task
+ * runs asynchronously even when timers are faked (e.g., in tests).
+ * 
+ * @param {() => void} task - The function to execute asynchronously.
+ * @returns {void}
+ */
 export default function enqueueTask(task: () => void): void {
   if (enqueueTaskImpl === null) {
     try {