feat: Passwordless cross-device authentication

- Arkitektur: docs/auth/passwordless-architecture.md
- Backend: iom/quixzoom-auth-service/ (FastAPI + Redis)
- Webb: quixzoom-market-pages/se/login/ (QR-kod + polling)
- App: iom/quixzoom-app/src/features/auth/ (push + deep links)

Flöde: QR-kod → app-godkännande → webb-inloggad

landvex-site/pilot/index.html

@@ -207,7 +207,7 @@
     }
     .process-step { text-align: center; padding: 0 20px; position: relative; }
     .step-num {
-      width: 54px; height: 54px; border-radius: 50%;
+      width: 54px; height: 54px; border-radius: var(--radius-full);
       background: var(--blue-glow); border: 2px solid var(--blue);
       display: flex; align-items: center; justify-content: center;
       font-size: 17px; font-weight: 800; color: var(--blue);
@@ -348,7 +348,7 @@
     .footer-links a { font-size: 14px; color: var(--text-muted); transition: color 0.2s; }
     .footer-links a:hover { color: #1d1d1f; }
     .footer-social {
-      width: 32px; height: 32px; border: 1px solid var(--border); border-radius: 8px;
+      width: 32px; height: 32px; border: 1px solid var(--border); border-radius: var(--radius-md);
       display: flex; align-items: center; justify-content: center;
       transition: border-color 0.2s, background 0.2s;
     }