Add billing-ending banner, events CRUD, RBIHF import, public API, team photos, and sponsors

A large batch of club-management features built up over one session:

- Club dashboard banner warning admins 1 month before billing ends
- Full Events/EventSeries CRUD (recurrence builder, occurrence lifecycle,
  per-team permissions), with match->game rename and game-specific fields
  (score, competition, live status, external game ID)
- Django-admin competition dropdown, gated per-club by feature flag
- Auto-import of RBIHF fixtures (scrape -> diff -> preview -> confirm),
  with location/opponent dropdowns suggested from existing club data
- Feature-flag-gated Shop/Forms nav sections, reusing the same flag
  machinery for the RBIHF import button
- Team roster now scoped to members active this season or next, sorted and
  grouped by position
- Club sport type (ice hockey / other), shown in the control panel's club
  subtitle
- Per-season team photo upload from the team page
- New public read-only API (Django Ninja) at /api/v1/: news, team rosters,
  upcoming/live/per-team games, and sponsors -- auto-documented via Swagger
  UI, CORS-enabled for a club's own external website
- Club sponsors: admin-only CRUD (logo, URL, active date window) plus a
  date-windowed, optionally randomized API endpoint
- Assorted fixes: NullBooleanField dropdown rendering, cross-club event
  validation timing, searchable-select chip placement, btn-neutral ->
  default button style sweep, calendar-month chart windows

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01R1gj3J1QPfP38XWpnpbFpy

teams/api.py

@@ -0,0 +1,122 @@
+"""Public read-only team/roster endpoints -- see api/urls.py for how this is
+mounted. Roster building is a small helper (build_roster) rather than
+inlined in the view so it can be unit-tested without going through Ninja's
+request cycle.
+"""
+
+import uuid
+from itertools import groupby
+
+from ninja import Router, Schema
+from ninja.errors import HttpError
+
+from api.errors import require_club
+from club.services.access import current_season
+
+from .models import Team, TeamMembership, TeamPhoto
+
+router = Router(tags=["teams"])
+
+
+class TeamOut(Schema):
+    id: uuid.UUID
+    name: str
+    short_name: str
+    photo_url: str | None
+
+
+class PlayerOut(Schema):
+    id: uuid.UUID
+    first_name: str
+    last_name: str
+    jersey_number: int | None
+    is_captain: bool
+    is_alternate_captain: bool
+
+
+class PositionGroupOut(Schema):
+    position: str
+    players: list[PlayerOut]
+
+
+class StaffMemberOut(Schema):
+    id: uuid.UUID
+    first_name: str
+    last_name: str
+    position: str
+
+
+class RosterOut(Schema):
+    team: TeamOut
+    season: str | None
+    players: list[PositionGroupOut]
+    staff: list[StaffMemberOut]
+
+
+def _to_team_out(team, request, photo=None) -> TeamOut:
+    photo_url = request.build_absolute_uri(photo.image.url) if photo else None
+    return TeamOut(id=team.pk, name=team.name, short_name=team.short_name, photo_url=photo_url)
+
+
+def _to_player_out(membership) -> PlayerOut:
+    return PlayerOut(
+        id=membership.member_id,
+        first_name=membership.member.first_name,
+        last_name=membership.member.last_name,
+        jersey_number=membership.jersey_number,
+        is_captain=membership.is_captain,
+        is_alternate_captain=membership.is_alternate_captain,
+    )
+
+
+def build_roster(team, request) -> RosterOut:
+    """Current season's players -- grouped by position (so a consumer can pull
+    just e.g. "Forward" without filtering a flat list itself), each group
+    sorted by jersey number, groups themselves in Position.ordering order --
+    and staff, for `team`. No current season -> empty roster, same "nothing
+    to show, not an error" handling as management.views.MembershipListView."""
+    season = current_season(team.club)
+    if season is None:
+        return RosterOut(team=_to_team_out(team, request), season=None, players=[], staff=[])
+
+    photo = TeamPhoto.objects.filter(team=team, season=season).first()
+
+    memberships = TeamMembership.objects.filter(team=team, season=season).select_related("member", "position").order_by("position__ordering", "position__name", "jersey_number")
+    assignments = team.staff_assignments.filter(season=season).select_related("member", "position").order_by("position__ordering", "position__name", "member__last_name")
+
+    # groupby only groups consecutive runs -- relies on the queryset already
+    # being ordered by position first, which it is.
+    players = [PositionGroupOut(position=position_name, players=[_to_player_out(m) for m in members]) for position_name, members in groupby(memberships, key=lambda m: m.position.name)]
+    staff = [
+        StaffMemberOut(id=assignment.member_id, first_name=assignment.member.first_name, last_name=assignment.member.last_name, position=assignment.position.name)
+        for assignment in assignments
+    ]
+
+    return RosterOut(team=_to_team_out(team, request, photo=photo), season=season.name, players=players, staff=staff)
+
+
+@router.get("/", response=list[TeamOut], summary="List teams")
+def list_teams(request):
+    club = require_club(request)
+    teams = list(Team.objects.filter(club=club).order_by("name"))
+
+    season = current_season(club)
+    photos_by_team_id = {}
+    if season is not None and teams:
+        photos_by_team_id = {photo.team_id: photo for photo in TeamPhoto.objects.filter(team__in=teams, season=season)}
+
+    return [_to_team_out(team, request, photo=photos_by_team_id.get(team.pk)) for team in teams]
+
+
+@router.get("/{team_id}/roster/", response=RosterOut, summary="Current season's roster")
+def get_roster(request, team_id: uuid.UUID):
+    club = require_club(request)
+    team = _get_team_or_404(club, team_id)
+    return build_roster(team, request)
+
+
+def _get_team_or_404(club, team_id):
+    team = Team.objects.filter(club=club, pk=team_id).first()
+    if team is None:
+        raise HttpError(404, "No such team.")
+    return team