Refactor Docker setup and frontend structure

- Updated Dockerfile to copy frontend files to meshchatx/public directory.
- Modified .dockerignore to include meshchatx/public.
- Added a new script to prepare the frontend directory.
- Adjusted Vite configuration to output to the new public directory.
- Updated GitHub Actions workflow to reflect changes in build process and artifact handling.

package.json

@@ -11,7 +11,8 @@
     "build": "npm run build-frontend && npm run build-backend",
     "electron-postinstall": "electron-builder install-app-deps",
     "electron": "npm run electron-postinstall && npm run build && electron .",
-    "dist": "npm run electron-postinstall && npm run build && electron-builder --publish=never"
+    "dist": "npm run electron-postinstall && npm run build && electron-builder --publish=never",
+    "dist-prebuilt": "npm run electron-postinstall && npm run build-backend && electron-builder --publish=never"
   },
   "license": "MIT",
   "engines": {