build: migrate from webpack to vite

[trim21]

Summary

Migrate the frontend build toolchain from webpack to Vite, and Storybook from @storybook/react-webpack5 to @storybook/react-vite. Use @lingui/vite-plugin for i18n catalog compilation instead of @lingui/loader.

Key Changes

Vite Configuration

• Created vite.config.ts with @vitejs/plugin-react, @lingui/vite-plugin, path aliases (@client, @shared), SCSS/PostCSS, dev server proxy (/api → http://127.0.0.1:3000), and production build output to dist/assets/
• Added client/src/vite-env.d.ts for Vite client type declarations
• Updated client/src/index.html with <script type="module" src="/javascript/app.tsx"> — Vite uses index.html as the entry point instead of a webpack entry config

Build Script

• Rewrote scripts/build.mjs to use Vite's build() API instead of webpack(). The esbuild server-bundle-with-embedded-assets step is unchanged.

Lingui Integration

• Catalog imports use ?lingui query parameter (e.g. import {messages} from './strings/en.json?lingui') instead of the webpack loader syntax @lingui/loader!./strings/en.json?raw-lingui
• Added declare module '*?lingui' in typings.d.ts so TypeScript understands the import shape without @ts-expect-error
• Updated languages.tsx and .storybook/preview.tsx

Storybook Migration

• Migrated from @storybook/react-webpack5 to @storybook/react-vite
• Replaced webpackFinal with viteFinal in .storybook/main.ts: mock aliases via resolve.alias (replaces NormalModuleReplacementPlugin), @lingui/vite-plugin for catalog compilation, SCSS config
• Removed @storybook/addon-webpack5-compiler-babel addon
• Updated all story file imports from @storybook/react-webpack5 → @storybook/react-vite

Asset & Import Changes

• CountryFlag.tsx: replaced webpack dynamic import() with Vite's import.meta.glob for flag images
• AboutTab.tsx: raw markdown import uses ?raw suffix instead of webpack raw-loader
• loadOverlayScrollbars.ts: replaced !raw-loader! inline syntax with ?raw suffix
• app.tsx: removed webpackPrefetch/webpackPreload magic comments

SCSS

• Removed ~ prefix from @import 'ress' in style.scss — Vite resolves bare specifiers from node_modules natively
• Silenced Sass import deprecation in Vite config (ress is a third-party CSS file that can't be converted to @use)

Runtime Fix

• FloodActions.ts: replaced global.document, global.setTimeout, global.clearTimeout with direct browser APIs — webpack polyfills global as window, Vite doesn't

Deleted Files

• client/config/webpack.config.dev.mjs
• client/config/webpack.config.prod.mjs
• client/scripts/development.mjs
• client/scripts/development.js
• client/scripts/utils/ (entire directory)
• client/config/ (entire directory)

Dependencies

Added: vite, @vitejs/plugin-react, @lingui/vite-plugin, @storybook/react-vite
Removed: webpack, webpack-dev-server, webpackbar, html-webpack-plugin, mini-css-extract-plugin, css-minimizer-webpack-plugin, terser-webpack-plugin, babel-loader, css-loader, postcss-loader, sass-loader, style-loader, source-map-loader, file-loader, raw-loader, case-sensitive-paths-webpack-plugin, eslint-webpack-plugin, @pmmmwh/react-refresh-webpack-plugin, react-refresh, @storybook/builder-webpack5, @storybook/react-webpack5, @storybook/addon-webpack5-compiler-babel, @lingui/loader
Kept: @babel/core, @babel/eslint-parser, @babel/preset-env, @babel/preset-react, @babel/preset-typescript (still used by ESLint's babelParser for .js/.jsx files and by @lingui/cli extraction)

Verification

• pnpm run check-types passes
• pnpm run lint passes (0 warnings)
• pnpm run build produces dist/assets/ (client) and dist/index.js (server with embedded assets)