fix: Google recurring event timezone + Outlook DST shift + Outlook delete

- Google: add timeZone to start/end objects when recurrence is present
  (fixes "Missing time zone definition for start time" error)
- Outlook: pass user timezone instead of UTC for event create/update,
  convert UTC dateTime to local representation (fixes +1h DST shift
  on recurring instances)
- Outlook: use instance ID for single-occurrence delete instead of
  series master ID (fixes ErrorItemNotFound on delete)

v1.63.1

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

package.json

@@ -1,6 +1,6 @@
 {
   "name": "my-weekly-todo-list",
-  "version": "1.63.0",
+  "version": "1.63.1",
   "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/lib/calendar-events.ts

@@ -847,11 +847,15 @@ export const createCalendarEvent = async (
 
     // Map to Google format
     const rrule = toRRule(event.recurrence, event.recurrenceEndDate, event.recurrenceCount, event.recurrenceInterval, event.recurrenceDays);
+    // Google requires timeZone on start/end when recurrence is present
+    const timezone = event.timezone || Intl.DateTimeFormat().resolvedOptions().timeZone || 'UTC';
+    const startObj = rrule ? { ...event.start, timeZone: timezone } : event.start;
+    const endObj = rrule ? { ...event.end, timeZone: timezone } : event.end;
     const googleEvent: any = {
       summary: event.title,
       description: event.description,
-      start: event.start,
-      end: event.end,
+      start: startObj,
+      end: endObj,
       location: event.location,
       ...(rrule ? { recurrence: [rrule] } : {}),
       ...(event.allDay ? { allDay: true } : {}),
@@ -891,11 +895,12 @@ export const createCalendarEvent = async (
     }
 
     const startDate = event.start?.dateTime ? new Date(event.start.dateTime) : new Date();
+    const outlookTz = event.timezone || Intl.DateTimeFormat().resolvedOptions().timeZone || 'UTC';
     const createdEvent = await createOutlookEvent(accessToken, calendarId, {
       summary: event.title,
       description: event.description,
-      start: event.start,
-      end: event.end,
+      start: { ...event.start, timeZone: outlookTz },
+      end: { ...event.end, timeZone: outlookTz },
       location: event.location,
       allDay: event.allDay,
       recurrence: toOutlookRecurrence(event.recurrence, startDate, event.recurrenceEndDate, event.recurrenceCount, event.recurrenceInterval, event.recurrenceDays),
@@ -1084,11 +1089,12 @@ export const updateCalendarEvent = async (
 
     // Map to Google format
     const rrule = toRRule(event.recurrence, event.recurrenceEndDate, event.recurrenceCount, event.recurrenceInterval, event.recurrenceDays);
+    const timezone = event.timezone || Intl.DateTimeFormat().resolvedOptions().timeZone || 'UTC';
     const googleEvent: any = {};
     if (event.title !== undefined) googleEvent.summary = event.title;
     if (event.description !== undefined) googleEvent.description = event.description;
-    if (event.start !== undefined) googleEvent.start = event.start;
-    if (event.end !== undefined) googleEvent.end = event.end;
+    if (event.start !== undefined) googleEvent.start = rrule ? { ...event.start, timeZone: timezone } : event.start;
+    if (event.end !== undefined) googleEvent.end = rrule ? { ...event.end, timeZone: timezone } : event.end;
     if (event.location !== undefined) googleEvent.location = event.location;
     if (rrule) googleEvent.recurrence = [rrule];
     if (event.url) googleEvent.source = { url: event.url, title: event.url };
@@ -1129,11 +1135,12 @@ export const updateCalendarEvent = async (
     const baseEventId = eventId.includes('::') ? eventId.split('::')[0] : eventId;
 
     const startDate = event.start?.dateTime ? new Date(event.start.dateTime) : new Date();
+    const outlookUpdateTz = event.timezone || Intl.DateTimeFormat().resolvedOptions().timeZone || 'UTC';
     const updatedEvent = await updateOutlookEvent(accessToken, calendarId, baseEventId, {
       summary: event.title,
       description: event.description,
-      start: event.start,
-      end: event.end,
+      start: event.start ? { ...event.start, timeZone: outlookUpdateTz } : undefined,
+      end: event.end ? { ...event.end, timeZone: outlookUpdateTz } : undefined,
       location: event.location,
       allDay: event.allDay,
       recurrence: toOutlookRecurrence(event.recurrence, startDate, event.recurrenceEndDate, event.recurrenceCount, event.recurrenceInterval, event.recurrenceDays),
@@ -1371,10 +1378,22 @@ export const deleteCalendarEvent = async (
       else throw new Error('Failed to refresh token');
     }
 
-    const baseEventId = eventId.includes('::') ? eventId.split('::')[0] : eventId;
-    // Outlook: for simplicity, always delete the series for now
-    // (Outlook instance deletion requires fetching specific occurrence IDs)
-    await deleteOutlookEvent(accessToken, calendarId, baseEventId);
+    // Outlook event ID format for recurring: "seriesMasterId::instanceId"
+    const hasInstanceId = eventId.includes('::');
+    const seriesMasterId = hasInstanceId ? eventId.split('::')[0] : eventId;
+    const instanceId = hasInstanceId ? eventId.split('::')[1] : eventId;
+
+    if (deleteMode === 'this' && hasInstanceId) {
+      // Delete just this specific occurrence
+      await deleteOutlookEvent(accessToken, calendarId, instanceId);
+    } else if (deleteMode === 'all' || !hasInstanceId) {
+      // Delete the entire series (use series master ID)
+      await deleteOutlookEvent(accessToken, calendarId, seriesMasterId);
+    } else {
+      // 'future' or 'past' — Outlook doesn't support partial series delete easily
+      // Fall back to deleting the series
+      await deleteOutlookEvent(accessToken, calendarId, seriesMasterId);
+    }
     return;
   } else if (connection.provider === 'apple') {
     const [email, appPassword] = connection.accessToken.split(':');

src/lib/outlook-calendar.ts

@@ -253,10 +253,20 @@ export const getUpcomingEvents = async (
 
 const ensureTimeZone = (dateTimeObj: any) => {
     if (!dateTimeObj) return dateTimeObj;
-    return {
-        dateTime: dateTimeObj.dateTime,
-        timeZone: dateTimeObj.timeZone || 'UTC'
-    };
+    const tz = dateTimeObj.timeZone || 'UTC';
+    let dt = dateTimeObj.dateTime;
+    // If dateTime is UTC (ends with Z) but we have a real timezone, convert to local representation
+    if (dt && typeof dt === 'string' && dt.endsWith('Z') && tz !== 'UTC') {
+        const d = new Date(dt);
+        // Format as local time in the target timezone: YYYY-MM-DDTHH:mm:ss.0000000
+        const parts = new Intl.DateTimeFormat('en-CA', {
+            timeZone: tz, year: 'numeric', month: '2-digit', day: '2-digit',
+            hour: '2-digit', minute: '2-digit', second: '2-digit', hour12: false
+        }).formatToParts(d);
+        const get = (type: string) => parts.find(p => p.type === type)?.value || '00';
+        dt = `${get('year')}-${get('month')}-${get('day')}T${get('hour')}:${get('minute')}:${get('second')}.0000000`;
+    }
+    return { dateTime: dt, timeZone: tz };
 };
 
 /**