feat(frontend): bootstrap Vite + React 19 + TS strict toolchain (F0.1)

- Vite 8 / React 19 / TS 6 strict (noUncheckedIndexedAccess, no baseUrl deprecation)
- Tailwind 4 via @tailwindcss/vite (no PostCSS step)
- TanStack Query 5, react-router-dom 7, Recharts, clsx
- Vitest + Testing Library + jsdom for unit tests
- Playwright skeleton + first smoke spec (login redirect)
- ESLint flat config: typescript-eslint type-checked, react-hooks, react-refresh, prettier
- Prettier config (semi, single quotes, 100-col, lf)
- IBM Plex font @font-face declarations targeting /fonts/ (self-host, no CDN — OPSEC)

frontend/vitest.config.ts

@@ -0,0 +1,25 @@
+import { defineConfig } from 'vitest/config';
+import react from '@vitejs/plugin-react';
+import tailwindcss from '@tailwindcss/vite';
+import path from 'node:path';
+
+export default defineConfig({
+  plugins: [react(), tailwindcss()],
+  resolve: {
+    alias: {
+      '@': path.resolve(__dirname, './src'),
+    },
+  },
+  test: {
+    globals: true,
+    environment: 'jsdom',
+    setupFiles: ['./src/test/setup.ts'],
+    css: true,
+    include: ['src/**/*.{test,spec}.{ts,tsx}'],
+    coverage: {
+      provider: 'v8',
+      reporter: ['text', 'html', 'lcov'],
+      exclude: ['node_modules/', 'src/test/', '**/*.config.*', '**/*.d.ts', 'src/main.tsx', 'src/mocks/**'],
+    },
+  },
+});