Regroup the management event list to match the member app's agenda look

The desktop "List" view was a flat, paginated <table>. It's now grouped the
same way mobile.views.CalendarView already groups the member app's own
calendar: "This week" / "Next week", then everything further out under its
own month divider -- same algorithm (itertools.groupby over an already-
sorted, already-paginated page of events), applied after pagination so the
two don't fight each other. "Show past events" mode skips the this/next-week
labels (they only make sense for what's ahead) and just groups straight into
months, most recent first.

Each row keeps the same information and admin actions the table had (kind
badge, series icon, teams, location, Edit/Delete) -- just laid out as a list
row instead of table cells, in its own reusable partial.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

management/views.py

@@ -1,3 +1,4 @@
+import itertools
 from datetime import date, timedelta
 from decimal import Decimal
 
@@ -2471,22 +2472,55 @@ class EventListView(ClubStaffRequiredMixin, ListView):
             calendar_nav = {"prev": add_months(anchor, -1), "next": add_months(anchor, 1)}
         return grid, calendar_nav
 
+    def _list_groups(self, events, show_past):
+        """The same This week/Next week/by-month agenda grouping mobile.views.
+        CalendarView uses (see that view's own docstring for the algorithm) --
+        applied to whichever page of `events` is actually being shown, so
+        pagination and grouping don't fight each other. Past mode (show_past=1,
+        already descending) skips the this/next-week special-casing -- those
+        labels only make sense for what's ahead -- and just groups straight
+        into months, most recent first."""
+        if not events:
+            return [], [], []
+
+        if show_past:
+            months = [{"month_start": month_start, "events": list(month_events)} for month_start, month_events in itertools.groupby(events, key=lambda event: timezone.localtime(event.start).date().replace(day=1))]
+            return [], [], months
+
+        today = timezone.localdate()
+        _this_week_start, this_week_end = week_bounds(today)
+        next_week_end = this_week_end + timedelta(days=7)
+
+        this_week, next_week, later = [], [], []
+        for event in events:
+            event_date = timezone.localtime(event.start).date()
+            if event_date <= this_week_end:
+                this_week.append(event)
+            elif event_date <= next_week_end:
+                next_week.append(event)
+            else:
+                later.append(event)
+
+        later_months = [{"month_start": month_start, "events": list(month_events)} for month_start, month_events in itertools.groupby(later, key=lambda event: timezone.localtime(event.start).date().replace(day=1))]
+        return this_week, next_week, later_months
+
     def get_context_data(self, **kwargs):
         club, user = self.request.club, self.request.user
         view_mode = self.request.GET.get("view", "calendar")
         range_kind = self.request.GET.get("range", "week")
         anchor = self._anchor_date()
         selected_season = selected_season_from_request(self.request, club)
+        show_past = self.request.GET.get("show_past") == "1"
 
         calendar, calendar_nav = (None, None)
         if view_mode == "calendar":
             calendar, calendar_nav = self._calendar_context(range_kind, anchor, selected_season)
 
-        return super().get_context_data(
+        context = super().get_context_data(
             seasons=Season.objects.filter(club=club).order_by("-start_date"),
             selected_season=selected_season,
             selected_kind=self.request.GET.get("kind", ""),
-            show_past=self.request.GET.get("show_past") == "1",
+            show_past=show_past,
             event_kinds=Event.EventKind.choices,
             can_create=is_club_admin(user, club) or teams_managed_by(user, club).exists(),
             view_mode=view_mode,
@@ -2503,6 +2537,11 @@ class EventListView(ClubStaffRequiredMixin, ListView):
             **kwargs,
         )
 
+        if view_mode == "list":
+            context["list_this_week"], context["list_next_week"], context["list_months"] = self._list_groups(context["events"], show_past)
+
+        return context
+
 
 class EventDetailView(ClubStaffRequiredMixin, DetailView):
     template_name = "management/event_detail.html"