Implement Standalone Android App via Flutter WebView

- Configured `vite.config.ts` for relative base path support.
- Initialized `mobile_app` Flutter project with `webview_flutter`.
- Added `assets/www` to Flutter assets configuration.
- Implemented `mobile_app/lib/main.dart` with WebView and Bridge API integration (Water Level Slider).
- Updated `.gitignore` for Flutter artifacts.
- Successfully built APK artifacts.

Co-authored-by: kliffdafunkfacekilla-arch <239708976+kliffdafunkfacekilla-arch@users.noreply.github.com>

mobile_app/assets/www/charges/ladder2.svg

@@ -0,0 +1,12 @@
+<svg xmlns="http://www.w3.org/2000/svg" fill="#d7374a" stroke="#000" viewBox="50 50 200 200">
+<metadata source="https://commons.wikimedia.org/wiki/File:H%C3%A9raldique_meuble_Echelle.svg" author="Bruno Vallette" license="https://www.gnu.org/licenses/fdl-1.3.html" />
+  <g id="ladder2" stroke-width="1" transform="translate(-28 57) scale(0.3)">
+    <rect width="16.99" height="253.007" x="381.76" y="17.773" rx="5.434" ry="16.344"/>
+    <rect width="16.99" height="253.007" x="456.859" y="17.773" rx="5.434" ry="16.344"/>
+    <rect width="72.65" height="12.244" x="391.48" y="220.837" rx="5.434" ry="16.344"/>
+    <rect width="72.65" height="12.244" x="391.48" y="180.721" rx="5.434" ry="16.344"/>
+    <rect width="72.65" height="12.244" x="391.48" y="140.606" rx="5.434" ry="16.344"/>
+    <rect width="72.65" height="12.244" x="391.48" y="100.49" rx="5.434" ry="16.344"/>
+    <rect width="72.65" height="12.244" x="391.48" y="60.375" rx="5.434" ry="16.344"/>
+  </g>
+</svg>