refactor(electron): migrate main process from CJS to ESM modules}
- Rename all Electron main process .js files to .mjs extension - Convert require()/module.exports to import/export default syntax - Replace dynamic require() calls with static imports and top-level await - Use createRequire() for package.json loading in ESM context - Add __filename/__dirname polyfills via import.meta.url - Replace `return` with `process.exit(0)` for early exit in ESM top-level - Use dynamic import() for electron-updater in menu click handler - Move translation require() calls to static ESM imports in app.mjs - Update package.json main entry point from app.js to app.mjs - Update start script to reference app.mjs - Bump version from 2026.4.104 to 2026.4.105 - Bump Node.js version from v24.14.0 to v24.14.1 - Upgrade electron from ^41.0.4 to ^41.1.0 - Fix trailing whitespace in angular.js and handler.js