fix: skip save during initial handleScrollFocus call

Wrap the initial handleScrollFocus call with isInitializing flag
to prevent handleScrollSave from incorrectly updating selected_task_id

static/js/tasks.js

@@ -162,8 +162,10 @@ function initScrollFocus() {
     scrollView.addEventListener("scroll", handleScrollFocus);
     scrollView.addEventListener("scroll", handleScrollSave);
 
-    // Initial call to set in-focus class
+    // Initial call to set in-focus class (skip saving during init)
+    isInitializing = true;
     handleScrollFocus();
+    isInitializing = false;
 }
 
 function handleScrollFocus() {