feat: remove admin video jobs link from navigation and update card background style

Co-authored-by: Copilot <copilot@github.com>

frontend/app/main.py

@@ -516,13 +516,6 @@ def admin_models():
     return render_template("admin/models.html")
 
 
-@app.get("/admin/videos")
-@admin_required
-def admin_videos():
-    """Show all video generation jobs across all users."""
-    return render_template("admin/videos.html")
-
-
 # ── Admin API proxies (same-origin for browser JS, avoids mixed-content) ──
 
 @app.get("/api/admin/videos")

frontend/app/static/style.css

@@ -615,7 +615,7 @@ main {
 
 /* Card */
 .card {
-  background: #fff;
+  background: rgba(255, 255, 255, 0.08);
   border-radius: 10px;
   padding: 2rem;
   box-shadow: 0 1px 4px rgba(0, 0, 0, 0.08);

frontend/app/templates/base.html

@@ -30,7 +30,6 @@
           <a href="{{ url_for('profile') }}">Profile</a>
           {% if session.get('user_role') == 'admin' %}
           <a href="{{ url_for('admin') }}">Admin</a>
-          <a href="{{ url_for('admin_videos') }}">Video Jobs</a>
           {% endif %}
           <a href="{{ url_for('logout') }}">Log out</a>
           {% else %}