- Reworked the tenant admin login page

- Updated the User model to implement Filament’s tenancy contracts
- Seeded a ready-to-use demo tenant (user, tenant, active package, purchase)
- Introduced a branded, translated 403 error page to replace the generic forbidden message for unauthorised admin hits
- Removed the public “Register” links from the marketing header
- hardened join event logic and improved error handling in the guest pwa.

docs/screenshots/tenant-admin-onboarding/05-event-setup.svg

@@ -0,0 +1,43 @@
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 1280 720">
+  <rect width="1280" height="720" fill="#f8fafc"/>
+  <text x="80" y="120" font-size="56" font-family="Inter, Arial, sans-serif" font-weight="700" fill="#0f172a">
+    Bereite dein erstes Event vor
+  </text>
+  <g transform="translate(80,180)">
+    <rect width="520" height="420" rx="24" fill="#ffffff" stroke="#e2e8f0" stroke-width="2"/>
+    <text x="40" y="80" font-size="28" font-family="Inter, Arial, sans-serif" fill="#1f2937">
+      Eventname
+    </text>
+    <rect x="40" y="100" width="440" height="56" rx="12" fill="#f1f5f9"/>
+    <text x="50" y="135" font-size="20" font-family="Inter, Arial, sans-serif" fill="#64748b">
+      Sommerfest Kreativagentur
+    </text>
+    <text x="40" y="180" font-size="28" font-family="Inter, Arial, sans-serif" fill="#1f2937">
+      Datum & Uhrzeit
+    </text>
+    <rect x="40" y="200" width="440" height="56" rx="12" fill="#f1f5f9"/>
+    <text x="50" y="235" font-size="20" font-family="Inter, Arial, sans-serif" fill="#64748b">
+      21.08.2025 – 18:00 Uhr
+    </text>
+    <text x="40" y="280" font-size="28" font-family="Inter, Arial, sans-serif" fill="#1f2937">
+      Sprache & Features
+    </text>
+    <text x="40" y="320" font-size="20" font-family="Inter, Arial, sans-serif" fill="#475569">
+      [x] Deutsche UI, [ ] Englische UI, [x] Aufgaben aktivieren, [x] Join-Token generieren
+    </text>
+    <rect x="40" y="360" width="200" height="56" rx="28" fill="#f43f5e"/>
+    <text x="60" y="398" font-size="24" font-family="Inter, Arial, sans-serif" fill="#ffffff">
+      Event erstellen
+    </text>
+  </g>
+  <g transform="translate(640,200)">
+    <rect width="520" height="320" rx="24" fill="#111827"/>
+    <text x="40" y="80" font-size="28" font-family="Inter, Arial, sans-serif" fill="#f8fafc">
+      Success States
+    </text>
+    <text x="40" y="130" font-size="22" font-family="Inter, Arial, sans-serif" fill="#cbd5f5">
+      Zeige „Event erstellt“ Toast und leite ins Dashboard weiter, sobald das Backend
+      den neuen Join-Token bestätigt hat.
+    </text>
+  </g>
+</svg>