feat(ui): platform control panel and styled auth screens

Add the `controlpanel` app: a platform-wide (not club-scoped) admin panel for
creating clubs, archiving/restoring them, managing club admins, and per-club
statistics (members, teams & staff, events, shop). Statistics are annotated in
one query so the club list cannot fan out into N+1, and are returned as stat
*groups* so growing the domain means adding one entry.

Two access rules, both enforced by PlatformStaffRequiredMixin:
- staff only (is_staff/is_superuser); anonymous are sent to login, signed-in
  non-staff get a 403. Staff already need a second factor, so the panel is
  2FA-protected for free.
- base domain only: the panel manages *all* clubs, so it 404s if the tenant
  middleware resolved a club from the subdomain.

Granting admin to an unknown email creates the account (unusable password —
they set one via password reset) and the Member behind it, since a ClubRole
hangs off a Member. A member who already holds a role is promoted in place,
because there is only one role per member per club.

UI is Tailwind + daisyUI. allauth ships an element system, so overriding
allauth/layouts/base.html plus ~13 element partials restyles *every* auth and
2FA screen at once — login, signup, password reset, the 2FA challenge, TOTP
enrolment, passkeys and recovery codes — rather than templating 20+ pages.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

clubmanager/settings.py

@@ -57,6 +57,7 @@ INSTALLED_APPS = [
     "events.apps.EventsConfig",
     "formbuilder.apps.FormbuilderConfig",
     "shop.apps.ShopConfig",
+    "controlpanel.apps.ControlpanelConfig",
 ]
 
 MIDDLEWARE = [