fix: faster calendar sync - 2min interval, sync on tab focus

- Reduced cache stale threshold from 15 minutes to 2 minutes
- Reduced background sync polling from 15 minutes to 2 minutes
- Added visibilitychange listener: syncs calendars and tasks when
  the user switches back to the tab (catches external edits in
  Apple Calendar, Google Calendar, etc.)

v1.74.7

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

package.json

@@ -1,6 +1,6 @@
 {
   "name": "my-weekly-todo-list",
-  "version": "1.74.6",
+  "version": "1.74.7",
   "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

@@ -2944,7 +2944,7 @@ export default function WeeklyView() {
         };
     }, [session]);
 
-    // Periodic background calendar cache refresh (every 15 minutes)
+    // Periodic background calendar cache refresh (every 2 minutes)
     useEffect(() => {
         if (!session) return;
         const interval = setInterval(
@@ -2974,11 +2974,24 @@ export default function WeeklyView() {
                     console.error("[SYNC] Calendar sync error:", e);
                 }
             },
-            15 * 60 * 1000,
+            2 * 60 * 1000,
         );
         return () => clearInterval(interval);
     }, [session, fetchCalendarEvents]);
 
+    // Sync when tab regains focus (catches external changes in other apps)
+    useEffect(() => {
+        if (!session) return;
+        const handleVisibility = () => {
+            if (!document.hidden) {
+                fetchCalendarEvents();
+                fetchTasks();
+            }
+        };
+        document.addEventListener('visibilitychange', handleVisibility);
+        return () => document.removeEventListener('visibilitychange', handleVisibility);
+    }, [session, fetchCalendarEvents]);
+
     async function fetchConnections() {
         try {
             setIsLoading(true);

src/lib/calendar-cache.ts

@@ -4,7 +4,7 @@
 import { prisma } from './prisma';
 import { getCalendarEvents, CalendarEvent, CalendarConnection } from './calendar-events';
 
-const STALE_THRESHOLD_MS = 15 * 60 * 1000; // 15 minutes — reduce API calls to providers
+const STALE_THRESHOLD_MS = 2 * 60 * 1000; // 2 minutes — keep in sync with external changes
 
 /**
  * Get the Monday (start of ISO week) for a given date.