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/src/api/client.ts

@@ -0,0 +1,42 @@
+// Client HTTP minimal. En dev, Vite proxifie `/api` vers le backend (:8000).
+const BASE_URL = import.meta.env.VITE_API_BASE_URL ?? '/api';
+
+export class ApiError extends Error {
+  constructor(
+    public readonly status: number,
+    public readonly body: unknown,
+  ) {
+    super(`API ${status}`);
+    this.name = 'ApiError';
+  }
+}
+
+async function request<T>(path: string, init?: RequestInit): Promise<T> {
+  const res = await fetch(`${BASE_URL}${path}`, {
+    ...init,
+    headers: {
+      'Content-Type': 'application/json',
+      ...init?.headers,
+    },
+    credentials: 'include',
+  });
+
+  const isJson = res.headers.get('content-type')?.includes('application/json');
+  const body = isJson ? await res.json() : await res.text();
+
+  if (!res.ok) {
+    throw new ApiError(res.status, body);
+  }
+  return body as T;
+}
+
+export const api = {
+  get: <T>(path: string) => request<T>(path),
+  post: <T>(path: string, data?: unknown) =>
+    request<T>(path, { method: 'POST', body: data === undefined ? undefined : JSON.stringify(data) }),
+  patch: <T>(path: string, data?: unknown) =>
+    request<T>(path, { method: 'PATCH', body: data === undefined ? undefined : JSON.stringify(data) }),
+  put: <T>(path: string, data?: unknown) =>
+    request<T>(path, { method: 'PUT', body: data === undefined ? undefined : JSON.stringify(data) }),
+  delete: <T>(path: string) => request<T>(path, { method: 'DELETE' }),
+};