feat: new TwoPointZero branding - icons, favicon, mockup i18n

- Replace extension icons with new TwoPointZero design (16/32/48/96/128)
- Update manifest.base.json with 32+96 icon sizes
- Increase popup logo to 48px, website nav logo to 64px
- Generate website webp sizes (64/128/200) + AVIF variants from 600px source
- Add favicon PNGs (16x16, 32x32) + apple-touch-icon + 192x192
- Fix logo vertical centering via display:contents on picture wrappers
- Convert mockup section from inline <span lang> pairs to {{MOCK_*}} template vars
- Add MOCK translations for FR, ES, PT-BR, RU locale files
- Bump AVIF quality 70->80, speed 6->4, remove min 3KB threshold
- Regenerate www/ with build.js

website/style.css

@@ -144,9 +144,16 @@ nav {
     letter-spacing: -0.5px;
 }
 
+.logo-area picture {
+    display: contents;
+}
+
 .logo-area img {
-    height: 40px;
-    width: 40px;
+    height: 64px;
+    width: 64px;
+    object-fit: contain;
+    border-radius: 8px;
+    margin: -4px 0;
 }
 
 .nav-ext-status {
@@ -262,7 +269,7 @@ nav {
     font-size: 0.95rem;
 }
 .btn-primary {
-    background: var(--accent);
+    background: #5b5de8;
     color: white;
     box-shadow: 0 10px 15px -3px var(--accent-glow);
 }
@@ -354,11 +361,15 @@ nav {
     font-weight: 800;
 }
 
+.mock-header-title picture {
+    display: contents;
+}
+
 .mock-header-title img {
-    width: 24px;
-    height: 24px;
+    width: 28px;
+    height: 28px;
     object-fit: contain;
-    border-radius: 4px;
+    border-radius: 6px;
 }
 
 .mock-version-link {