fix: sync spinner disappearing prematurely during concurrent fetches

When both fetchCalendarEvents and fetchTasks ran in parallel, whichever
finished first would set isSyncing=false, hiding the spinner while the
other was still running. Replaced boolean with a ref-based counter so
the spinner stays visible until all concurrent syncs complete.

v1.3.1

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

package.json

@@ -1,6 +1,6 @@
 {
   "name": "my-weekly-todo-list",
-  "version": "1.3.0",
+  "version": "1.3.1",
   "description": "A web-based weekly task management application that organizes to-dos and calendar events in a single, intuitive weekly view",
   "main": "index.js",
   "scripts": {

src/components/WeeklyView.tsx

@@ -483,6 +483,9 @@ export default function WeeklyView() {
     const [viewDays, setViewDays] = useState(7);
     const [isLoading, setIsLoading] = useState(true);
     const [isSyncing, setIsSyncing] = useState(false);
+    const syncCountRef = useRef(0);
+    const startSync = useCallback(() => { syncCountRef.current++; setIsSyncing(true); }, []);
+    const endSync = useCallback(() => { syncCountRef.current = Math.max(0, syncCountRef.current - 1); if (syncCountRef.current === 0) setIsSyncing(false); }, []);
     const [darkMode, setDarkMode] = useState(false);
     const [timeFormat, setTimeFormat] = useState("24h");
     const [dateFormat, setDateFormat] = useState("yyyy-MM-dd");
@@ -859,7 +862,7 @@ export default function WeeklyView() {
 
     // Fetch calendar events
     const fetchCalendarEvents = useCallback(async (forceRefresh = false) => {
-        setIsSyncing(true);
+        startSync();
         try {
             const response = await fetch("/api/calendar/sync", {
                 method: "POST",
@@ -890,7 +893,7 @@ export default function WeeklyView() {
         } catch (error) {
             console.error("Error fetching calendar events:", error);
         } finally {
-            setIsSyncing(false);
+            endSync();
         }
     }, [currentWeekStart]);
 
@@ -1399,7 +1402,7 @@ export default function WeeklyView() {
     }
 
     async function fetchTasks() {
-        setIsSyncing(true);
+        startSync();
         try {
             const [tasksResponse, listsResponse] = await Promise.all([
                 fetch("/api/tasks"),
@@ -1489,7 +1492,7 @@ export default function WeeklyView() {
             console.error("Error fetching data:", error);
         } finally {
             setIsLoading(false);
-            setIsSyncing(false);
+            endSync();
         }
     }