fix: include events without dtend_utc in upcoming events filter

Events without an end time are now included in the response if their start time is within 90 minutes before now. This ensures events without dtend_utc are properly shown as "live" for 90 minutes after they start.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

Author: tonyqiu123

backend/apps/events/views.py

@@ -73,10 +73,16 @@ def get_events(request):
         # Upcoming events filter: show all live and future events by default
         if not dtstart_utc_param:
             now = timezone.now()
+            ninety_minutes_ago = now - timedelta(minutes=90)
             events_queryset = events_queryset.filter(
                 Q(
                     event_dates__dtstart_utc__lte=now, event_dates__dtend_utc__gte=now
-                )  # Live
+                )  # Live events with dtend_utc
+                | Q(
+                    event_dates__dtstart_utc__gte=ninety_minutes_ago,
+                    event_dates__dtstart_utc__lte=now,
+                    event_dates__dtend_utc__isnull=True
+                )  # Live events without dtend_utc (started within last 90 minutes)
                 | Q(event_dates__dtstart_utc__gte=now)  # Upcoming
             ).distinct()
         else:
@@ -175,18 +181,24 @@ def get_events(request):
 
         for event in events_list:
             all_dates = list(event.event_dates.all())
+            ninety_minutes_ago = now - timedelta(minutes=90)
             # Find the next upcoming or currently live date
             upcoming_or_live_dates = [
                 date
                 for date in all_dates
                 if date.dtstart_utc
                 and (
-                    date.dtstart_utc >= now
+                    date.dtstart_utc >= now  # Future events
                     or (
                         date.dtstart_utc <= now
                         and date.dtend_utc
                         and date.dtend_utc >= now
-                    )
+                    )  # Live events with dtend_utc
+                    or (
+                        date.dtstart_utc >= ninety_minutes_ago
+                        and date.dtstart_utc <= now
+                        and not date.dtend_utc
+                    )  # Live events without dtend_utc (started within last 90 minutes)
                 )
             ]
             selected_date = (