feat(01-01): React + Vite + Tailwind v4 SPA scaffold con API client

- Vite react-ts project con base: '/postgenerator/' (Pitfall #9 risolto)
- Tailwind v4 via @tailwindcss/vite plugin + @import "tailwindcss" in index.css
- react-router-dom con BrowserRouter basename="/postgenerator"
- @tanstack/react-query con QueryClientProvider
- lucide-react installato per icone
- src/api/client.ts: API_BASE='/postgenerator/api', apiFetch<T> con error handling
- Dev proxy: /postgenerator/api -> http://localhost:8000 (strip /postgenerator)
- App.tsx: HomePage placeholder "Setup completo", struttura Routes pronta
- Build Vite: 253.90kB JS + 5.53kB CSS, nessun errore TypeScript

frontend/eslint.config.js

@@ -0,0 +1,23 @@
+import js from '@eslint/js'
+import globals from 'globals'
+import reactHooks from 'eslint-plugin-react-hooks'
+import reactRefresh from 'eslint-plugin-react-refresh'
+import tseslint from 'typescript-eslint'
+import { defineConfig, globalIgnores } from 'eslint/config'
+
+export default defineConfig([
+  globalIgnores(['dist']),
+  {
+    files: ['**/*.{ts,tsx}'],
+    extends: [
+      js.configs.recommended,
+      tseslint.configs.recommended,
+      reactHooks.configs.flat.recommended,
+      reactRefresh.configs.vite,
+    ],
+    languageOptions: {
+      ecmaVersion: 2020,
+      globals: globals.browser,
+    },
+  },
+])