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>

templates/allauth/elements/details.html

@@ -0,0 +1,5 @@
+{% load allauth %}
+<details class="collapse-arrow collapse border border-base-300 bg-base-100 my-2" {% if attrs.open %}open{% endif %}>
+    <summary class="collapse-title font-medium">{% slot summary %}{% endslot %}</summary>
+    <div class="collapse-content">{% slot body %}{% endslot %}</div>
+</details>