feat: complete tOS project with HR, LEAN, Dashboard and Integrations modules

Full enterprise web operating system including:
- Next.js 14 frontend with App Router, i18n (DE/EN), shadcn/ui
- NestJS 10 backend with Prisma, JWT auth, Swagger docs
- Keycloak 24 SSO with role-based access control
- HR module (employees, time tracking, absences, org chart)
- LEAN module (3S planning, morning meeting SQCDM, skill matrix)
- Integrations module (PlentyONE, Zulip, Todoist, FreeScout, Nextcloud, ecoDMS, GembaDocs)
- Dashboard with customizable drag & drop widget grid
- Docker Compose infrastructure (PostgreSQL 16, Redis 7, Keycloak 24)

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

apps/web/src/lib/api.ts

@@ -0,0 +1,120 @@
+import { getSession } from 'next-auth/react';
+
+const API_URL = process.env.NEXT_PUBLIC_API_URL || 'http://localhost:3001/api';
+
+/**
+ * API client configuration
+ */
+interface RequestConfig extends RequestInit {
+  params?: Record<string, string | number | boolean | undefined>;
+}
+
+/**
+ * Build URL with query parameters
+ */
+function buildUrl(endpoint: string, params?: RequestConfig['params']): string {
+  const url = new URL(`${API_URL}${endpoint}`);
+
+  if (params) {
+    Object.entries(params).forEach(([key, value]) => {
+      if (value !== undefined) {
+        url.searchParams.append(key, String(value));
+      }
+    });
+  }
+
+  return url.toString();
+}
+
+/**
+ * Make an authenticated API request
+ */
+async function request<T>(endpoint: string, config: RequestConfig = {}): Promise<T> {
+  const { params, ...init } = config;
+
+  // Get session for auth token
+  const session = await getSession();
+
+  const headers: HeadersInit = {
+    'Content-Type': 'application/json',
+    ...(init.headers || {}),
+  };
+
+  // Add auth header if session exists
+  if (session?.accessToken) {
+    (headers as Record<string, string>)['Authorization'] = `Bearer ${session.accessToken}`;
+  }
+
+  const response = await fetch(buildUrl(endpoint, params), {
+    ...init,
+    headers,
+  });
+
+  // Handle non-OK responses
+  if (!response.ok) {
+    const error = await response.json().catch(() => ({ message: 'An error occurred' }));
+    throw new Error(error.message || `HTTP error ${response.status}`);
+  }
+
+  // Handle empty responses
+  const contentType = response.headers.get('content-type');
+  if (contentType?.includes('application/json')) {
+    return response.json();
+  }
+
+  return {} as T;
+}
+
+/**
+ * API client with typed methods
+ */
+export const api = {
+  /**
+   * GET request
+   */
+  get<T>(endpoint: string, config?: RequestConfig): Promise<T> {
+    return request<T>(endpoint, { ...config, method: 'GET' });
+  },
+
+  /**
+   * POST request
+   */
+  post<T>(endpoint: string, data?: unknown, config?: RequestConfig): Promise<T> {
+    return request<T>(endpoint, {
+      ...config,
+      method: 'POST',
+      body: data ? JSON.stringify(data) : undefined,
+    });
+  },
+
+  /**
+   * PUT request
+   */
+  put<T>(endpoint: string, data?: unknown, config?: RequestConfig): Promise<T> {
+    return request<T>(endpoint, {
+      ...config,
+      method: 'PUT',
+      body: data ? JSON.stringify(data) : undefined,
+    });
+  },
+
+  /**
+   * PATCH request
+   */
+  patch<T>(endpoint: string, data?: unknown, config?: RequestConfig): Promise<T> {
+    return request<T>(endpoint, {
+      ...config,
+      method: 'PATCH',
+      body: data ? JSON.stringify(data) : undefined,
+    });
+  },
+
+  /**
+   * DELETE request
+   */
+  delete<T>(endpoint: string, config?: RequestConfig): Promise<T> {
+    return request<T>(endpoint, { ...config, method: 'DELETE' });
+  },
+};
+
+export default api;