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

quixzoom-landing-fixed/join.html

@@ -67,7 +67,7 @@
     }
     .card {
       background: var(--ios-card);
-      border-radius: 16px;
+      border-radius: var(--radius-lg);
       padding: 20px;
       margin-bottom: 16px;
     }
@@ -83,7 +83,7 @@
     .field-input {
       width: 100%;
       padding: 14px;
-      border-radius: 10px;
+      border-radius: var(--radius-md);
       border: 1px solid var(--ios-gray);
       background: var(--ios-bg);
       color: var(--ios-text);
@@ -92,7 +92,7 @@
     .btn {
       width: 100%;
       padding: 16px;
-      border-radius: 12px;
+      border-radius: var(--radius-md);
       border: none;
       background: var(--ios-blue);
       color: white;
@@ -111,7 +111,7 @@
     .feature-icon {
       width: 40px;
       height: 40px;
-      border-radius: 10px;
+      border-radius: var(--radius-md);
       background: var(--ios-green);
       display: flex;
       align-items: center;
@@ -135,21 +135,21 @@
 
   <div class="features">
     <div class="feature">
-      <div class="feature-icon">📸</div>
+      <div class="feature-icon"></div>
       <div class="feature-text">
         <h3>Take Photos</h3>
         <p>Complete missions near you with your phone</p>
       </div>
     </div>
     <div class="feature">
-      <div class="feature-icon">💰</div>
+      <div class="feature-icon"></div>
       <div class="feature-text">
         <h3>Get Paid</h3>
         <p>Earn $5-50 per mission, paid every Monday</p>
       </div>
     </div>
     <div class="feature">
-      <div class="feature-icon">🕐</div>
+      <div class="feature-icon"></div>
       <div class="feature-text">
         <h3>Flexible Hours</h3>
         <p>Work when you want, where you want</p>