fix(webui): add Noto Sans font support for Cyrillic text (#8015)

The WebUI only loaded Noto Sans SC (Simplified Chinese), which lacks
Cyrillic glyphs. Russian text fell back to system sans-serif, causing
poor rendering depending on the OS.

Changes:
- Load Noto Sans (regular) from Google Fonts alongside Noto Sans SC
- Add 'Noto Sans' at the END of $cjk-sans-fallback (after CJK fonts)
  so Chinese text still renders with system CJK fonts first,
  while Cyrillic text falls through to Noto Sans.

This ensures both Chinese and Cyrillic text render correctly.

Author: Midwich

dashboard/index.html

@@ -9,7 +9,7 @@
     <meta name="robots" content="noindex, nofollow" />
     <link
       rel="stylesheet"
-      href="https://fonts.googleapis.com/css2?family=Outfit&family=Noto+Sans+SC:wght@100..900&display=swap"
+      href="https://fonts.googleapis.com/css2?family=Outfit&family=Noto+Sans:wght@100..900&family=Noto+Sans+SC:wght@100..900&display=swap"
     />
     <!-- VAD (Voice Activity Detection) Libraries -->
     <script src="https://cdn.jsdelivr.net/npm/onnxruntime-web@1.22.0/dist/ort.wasm.min.js"></script>

dashboard/src/scss/_variables.scss

@@ -9,7 +9,7 @@ $color-pack: false;
 // Global font size and border radius
 $font-size-root: 1rem;
 $border-radius-root: 8px;
-$cjk-sans-fallback: 'PingFang SC', 'Hiragino Sans GB', 'Noto Sans CJK SC', 'Microsoft YaHei' !default;
+$cjk-sans-fallback: 'PingFang SC', 'Hiragino Sans GB', 'Noto Sans CJK SC', 'Microsoft YaHei', 'Noto Sans SC', 'Noto Sans' !default;
 $cjk-mono-fallback: 'PingFang SC', 'PingFang TC', 'Hiragino Sans GB', 'Noto Sans CJK SC', 'Microsoft YaHei' !default;
 $code-text-color: #111827 !default;