Migrate to electron-vite and electron-builder

- Switch from deprecated Vue CLI plugin to `electron-vite` (see
  nklayman/vue-cli-plugin-electron-builder#1982)
- Update main/preload scripts to use `index.cjs` filenames to support
  `"type": "module"`, resolving crash issue (#233). This crash was
  related to Electron not supporting ESM (see electron/asar#249,
  electron/electron#21457).
- This commit completes migration to Vite from Vue CLI (#230).

Structure changes:

- Introduce separate folders for Electron's main and preload processes.
- Move TypeHelpers to `src/` to mark tit as accessible by the rest of
  the code.

Config changes:

- Make `vite.config.ts` reusable by Electron configuration.
- On electron-builder, use `--publish` flag instead of `-p` for clarity.

Tests:

- Add log for preload script loading verification.
- Implement runtime environment sanity checks.
- Enhance logging in `check-desktop-runtime-errors`.

scripts/check-desktop-runtime-errors/utils/npm.js

@@ -15,7 +15,7 @@ export async function npmInstall(projectDir) {
   if (!projectDir) { throw new Error('missing project directory'); }
   const npmModulesPath = join(projectDir, 'node_modules');
   if (!await isDirMissingOrEmpty(npmModulesPath)) {
-    log(`Directory "${npmModulesPath}" exists and has content. Skipping 'npm install'.`);
+    log(`Directory "${npmModulesPath}" exists and has content. Skipping \`npm install\`.`);
     return;
   }
   log('Starting dependency installation...');