Landing: visible navbar with page links, remove price from dashboard

- Nav background visible immediately (semi-transparent dark with blur)
- Added Инструменты and Возможности links in nav (hidden on mobile)
- Added id=features to advantages section for smooth scroll
- Replaced 0₽ with Free label on dashboard about section

public/index.html

@@ -174,8 +174,8 @@
                 <div class="label">категории</div>
             </div>
             <div class="about-stat">
-                <div class="num">0 &#8381;</div>
-                <div class="label">навсегда</div>
+                <div class="num" style="color:#22c55e;">Free</div>
+                <div class="label">бесплатно</div>
             </div>
         </div>
     </div>

public/landing.html

@@ -282,6 +282,7 @@
             gap: 20px;
         }
         @media (min-width: 640px) {
+            .nav-link { display:inline-flex; }
             .cat-grid { grid-template-columns: repeat(2, 1fr); }
         }
         @media (min-width: 1024px) {
@@ -489,7 +490,7 @@
             align-items: center;
             justify-content: space-between;
             padding: 16px 32px;
-            background: rgba(6, 12, 24, 0);
+            background: rgba(6, 12, 24, 0.7); backdrop-filter: blur(12px);
             border-bottom: 1px solid transparent;
             transition: background 0.3s, border-color 0.3s, backdrop-filter 0.3s;
         }
@@ -522,6 +523,10 @@
             padding: 8px 4px;
         }
         .nav-link:hover { color: var(--text-primary); }
+        .nav-link.nav-page { display: none; }
+        @media (min-width: 768px) {
+            .nav-link.nav-page { display: inline-flex; }
+        }
         .nav-btn {
             font-family: 'Manrope', sans-serif;
             font-size: 14px;
@@ -588,6 +593,8 @@
 <nav class="landing-nav" id="mainNav">
     <a href="/" class="nav-logo">WA Dev <span>Tools</span></a>
     <div class="nav-actions">
+        <a href="#tools" class="nav-link nav-page">Инструменты</a>
+        <a href="#features" class="nav-link nav-page">Возможности</a>
         <a href="/auth/login" class="nav-link">Войти</a>
         <a href="/auth/register" class="nav-btn">Регистрация</a>
     </div>
@@ -774,7 +781,7 @@
 <!-- ════════════════════════════════════════════
      ADVANTAGES
 ════════════════════════════════════════════ -->
-<section class="adv-section">
+<section class="adv-section" id="features">
     <div style="max-width:1120px;margin:0 auto;">
         <div class="adv-grid">