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/ploughshare.svg

@@ -0,0 +1,6 @@
+<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:Coa_Illustration_Elements_Tool_Plow.svg" author="Madboy74" license="https://www.gnu.org/licenses/fdl-1.3.html"/>
+  <g id="ploughshare" stroke-width=".8">
+    <path d="M131.1 61.64c.53 18.36-2.27 44.66-18.31 66.8l-11.4-8.9c-1.41-1.1-3.31-1.27-4.57-.01a3.25 3.25 0 00.74 5.13l-14.47 14.47-14.74-14.73zM86 126.92a3.23 3.23 0 00-4.56 4.57 3.23 3.23 0 004.57-4.57z"/>
+  </g>
+</svg>