Frontend : squelette React + Vite + TS + Tailwind

Scaffold de base en attendant l'intégration du design Claude Design
(« Bénévoles Festival.dc.html ») : routage, plomberie i18n (t() +
locales/fr.json), client API avec proxy Vite vers le backend. Build et
lint passent.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01AwswqSChc3Rwtu61pRXiY2

frontend/eslint.config.js

@@ -0,0 +1,25 @@
+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';
+
+export default tseslint.config(
+  { ignores: ['dist'] },
+  {
+    extends: [js.configs.recommended, ...tseslint.configs.recommended],
+    files: ['**/*.{ts,tsx}'],
+    languageOptions: {
+      ecmaVersion: 2020,
+      globals: globals.browser,
+    },
+    plugins: {
+      'react-hooks': reactHooks,
+      'react-refresh': reactRefresh,
+    },
+    rules: {
+      ...reactHooks.configs.recommended.rules,
+      'react-refresh/only-export-components': ['warn', { allowConstantExport: true }],
+    },
+  },
+);