docs(#43): 📝 Add JSdocs describing what the functions in this fi…

src/AnnotationControl/persistence.js

@@ -1,3 +1,28 @@
+/**
+ * Annotation persistence.
+ * - Loads annotations from JSON and rebuilds the live tree.
+ * - Serializes live annotations (title, description, position, cameraPosition).
+ * - Autosaves to server (saveUrl) and localStorage on changes.
+ *
+ * Usage (minimal):
+ *   const api = initAnnotationPersistence(viewer, { jsonUrl: '/annotations/annotations.json' })
+ *   // api: { getAnnotationsJSON, saveToServer, snapshotToLocalStorage, loadFromJson, serializeGrouped }
+ */
+
+/**
+ * Initialize annotation persistence.
+ * @param {Potree.Viewer} viewer - Potree viewer with scene.annotations as root
+ * @param {Object} [options]
+ * @param {string} [options.jsonUrl] - URL to fetch/load annotations JSON
+ * @param {string} [options.saveUrl] - URL to POST saved JSON (defaults set automatically)
+ * @returns {{
+ *   getAnnotationsJSON: function(): object,
+ *   saveToServer: function(object=): Promise<object>,
+ *   snapshotToLocalStorage: function(): void,
+ *   loadFromJson: function(): Promise<void>,
+ *   serializeGrouped: function(): object
+ * }}
+ */
 export function initAnnotationPersistence(viewer, options = {}) {
   const jsonUrl = options.jsonUrl || '/annotations/annotations.json'
   const defaultSaveUrl = (() => {
@@ -255,7 +280,7 @@ export function initAnnotationPersistence(viewer, options = {}) {
             last = cur
             debouncedSnapshot()
           }
-          if (frames++ < 90) requestAnimationFrame(poll) // ~1.5s at 60fps
+          if (frames++ < 90) requestAnimationFrame(poll)
         }
         requestAnimationFrame(poll)
       }