Checkpoint: management app redesign, onboarding/signup workflow, and events calendar backend

Large uncommitted body of work accumulated across sessions on this branch --
committing as a checkpoint so it's tracked and future worktree-isolated agents
see the real codebase instead of a stale ancestor commit. Covers the
management app's dedicated Tailwind theme and templates, the club onboarding
requirement/signup workflow (club/services/onboarding.py, requirement/status
models, sign-up dashboard), fee/status auto-activation decoupling, referee
management, and the new events calendar grid service layer.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01ECGMEwrc2k4D8VQuwjstj9

club/tasks.py

@@ -0,0 +1,34 @@
+"""Celery task behind the `generate-seasons` beat schedule entry (see
+rosterchief/settings.CELERY_BEAT_SCHEDULE and features/jobs.py).
+
+Mirrors `manage.py generate_seasons`'s default behaviour (generate, not --resync) exactly --
+that command still exists, unchanged, for manual use from a shell, including --resync, which
+this task deliberately does not run unattended (see club/management/commands/generate_seasons.py:
+--resync can delete rows, so it isn't something a beat schedule should do on its own).
+"""
+
+from celery import shared_task
+from dateutil.relativedelta import relativedelta
+from django.utils import timezone
+
+from club.models import Club
+from club.services.seasons import generate_seasons as generate_seasons_for_club
+from features.models import Maintenance
+
+#: How far ahead to generate, matching the management command's own default.
+YEARS_AHEAD = 2
+
+
+@shared_task(name="club.tasks.generate_seasons")
+def generate_seasons():
+    if Maintenance.is_on():
+        raise RuntimeError("Platform is in maintenance mode; this job stood down.")
+
+    until = timezone.localdate() + relativedelta(years=YEARS_AHEAD)
+    clubs = Club.objects.active()
+
+    total = 0
+    for club in clubs:
+        total += len(generate_seasons_for_club(club, until))
+
+    return f"Generated {total} season(s) across {clubs.count()} club(s)."