feat: add centralized authenticated API request handler for mobile (#338)

Author: Midoriya-w

apps/mobile/src/utils/apiClient.ts

@@ -0,0 +1,36 @@
+import { API_BASE_URL } from '../config';
+
+type RequestOptions = {
+  method?: 'GET' | 'POST' | 'PUT' | 'PATCH' | 'DELETE';
+  body?: unknown;
+  token: string | null;
+  onUnauthorized?: () => void;
+};
+
+export async function apiRequest<T>(
+  endpoint: string,
+  { method = 'GET', body, token, onUnauthorized }: RequestOptions
+): Promise<T> {
+  const headers: HeadersInit = {
+    'Content-Type': 'application/json',
+    ...(token ? { Authorization: `Bearer ${token}` } : {}),
+  };
+
+  const response = await fetch(`${API_BASE_URL}${endpoint}`, {
+    method,
+    headers,
+    ...(body ? { body: JSON.stringify(body) } : {}),
+  });
+
+  if (response.status === 401 || response.status === 403) {
+    onUnauthorized?.();
+    throw new Error('Unauthorized');
+  }
+
+  if (!response.ok) {
+    const error = await response.json().catch(() => ({}));
+    throw new Error(error?.message ?? `Request failed: ${response.status}`);
+  }
+
+  return response.json() as Promise<T>;
+}