Show blurred spacer.png overlay on members/wiki sections when not logged in

- Instead of hiding main-content, members and wiki sections stay visible
- Each section has a .section-locked overlay with spacer.png blurred 16px
- Semi-transparent white layer + frosted-glass CTA card on top
- CTA says 'Login via Telegram' with the same bot deep-link as Anmelden
- checkSession() now toggles overlay visibility instead of hiding the whole main

index.html

@@ -358,6 +358,31 @@
 
     <!-- Members Section -->
     <section class="section section-alt fade-in-section" id="members">
+      <div class="section-locked" id="members-locked">
+        <img class="locked-bg" src="/spacer.png" alt="" aria-hidden="true">
+        <div class="locked-overlay"></div>
+        <div class="locked-cta">
+          <div class="locked-cta-content">
+            <div class="locked-icon">🔒</div>
+            <h3 class="locked-title">
+              <span class="hide-de">Exklusiver Mitgliederbereich</span>
+              <span class="hide-en">Exclusive Members Area</span>
+            </h3>
+            <p class="locked-desc">
+              <span class="hide-de">Melde dich über Telegram an, um Zugriff auf unsere Mitgliederliste, das Wiki und alle Inhalte zu erhalten.</span>
+              <span class="hide-en">Sign in via Telegram to get access to our member directory, wiki, and everything else.</span>
+            </p>
+            <a href="https://t.me/YourBotUsername?start=send_a_login_link" target="_blank" rel="noopener" class="btn btn-primary locked-login-btn">
+              <span class="hide-de">Per Telegram anmelden</span>
+              <span class="hide-en">Login via Telegram</span>
+            </a>
+            <p class="locked-hint">
+              <span class="hide-de">Nach der Anmeldung erhältst du in Telegram einen Link, der dich hier freischaltet.</span>
+              <span class="hide-en">After signing in you will receive a link in Telegram that unlocks this page.</span>
+            </p>
+          </div>
+        </div>
+      </div>
       <div class="container">
         <h2 class="section-title">
           <span class="hide-de">Mitglieder</span>
@@ -378,6 +403,27 @@
 
     <!-- Wiki Section -->
     <section class="section fade-in-section" id="wiki">
+      <div class="section-locked" id="wiki-locked">
+        <img class="locked-bg" src="/spacer.png" alt="" aria-hidden="true">
+        <div class="locked-overlay"></div>
+        <div class="locked-cta">
+          <div class="locked-cta-content">
+            <div class="locked-icon">🔒</div>
+            <h3 class="locked-title">
+              <span class="hide-de">Exklusiver Wiki-Bereich</span>
+              <span class="hide-en">Exclusive Wiki Area</span>
+            </h3>
+            <p class="locked-desc">
+              <span class="hide-de">Melde dich über Telegram an, um auf unser Wiki mit allen Erfahrungen zu Steuern, Banken und Rechtlichem zuzugreifen.</span>
+              <span class="hide-en">Sign in via Telegram to access our wiki with all experiences on taxes, banking and legal matters.</span>
+            </p>
+            <a href="https://t.me/YourBotUsername?start=send_a_login_link" target="_blank" rel="noopener" class="btn btn-primary locked-login-btn">
+              <span class="hide-de">Per Telegram anmelden</span>
+              <span class="hide-en">Login via Telegram</span>
+            </a>
+          </div>
+        </div>
+      </div>
       <div class="container">
         <h2 class="section-title">
           <span class="hide-de">Wiki</span>