feat: Implement backend API and basic frontend structure

Adds initial backend API endpoints for fetching users and attendances, including basic filtering. Sets up the frontend routing with a layout component and includes placeholder pages for dashboard, users, and login. Refactors the README for local development setup.

services/dataService.ts

@@ -0,0 +1,68 @@
+
+import { Attendance, DashboardFilter, User } from '../types';
+
+// URL do Backend que criamos (backend/index.js)
+// Certifique-se de rodar o backend com 'node backend/index.js'
+const API_URL = 'http://localhost:3001/api'; 
+
+export const getAttendances = async (tenantId: string, filter: DashboardFilter): Promise<Attendance[]> => {
+  try {
+    const params = new URLSearchParams();
+    params.append('tenantId', tenantId);
+    
+    if (filter.dateRange.start) params.append('startDate', filter.dateRange.start.toISOString());
+    if (filter.dateRange.end) params.append('endDate', filter.dateRange.end.toISOString());
+    
+    if (filter.userId && filter.userId !== 'all') params.append('userId', filter.userId);
+    if (filter.teamId && filter.teamId !== 'all') params.append('teamId', filter.teamId);
+
+    const response = await fetch(`${API_URL}/attendances?${params.toString()}`);
+    
+    if (!response.ok) {
+      throw new Error('Falha ao buscar atendimentos do servidor');
+    }
+
+    return await response.json();
+  } catch (error) {
+    console.error("API Error (getAttendances):", error);
+    // Fallback vazio ou lançar erro para a UI tratar
+    return []; 
+  }
+};
+
+export const getUsers = async (tenantId: string): Promise<User[]> => {
+  try {
+    const params = new URLSearchParams();
+    if (tenantId !== 'all') params.append('tenantId', tenantId);
+
+    const response = await fetch(`${API_URL}/users?${params.toString()}`);
+    if (!response.ok) throw new Error('Falha ao buscar usuários');
+    
+    return await response.json();
+  } catch (error) {
+    console.error("API Error (getUsers):", error);
+    return [];
+  }
+};
+
+export const getUserById = async (id: string): Promise<User | undefined> => {
+  try {
+    const response = await fetch(`${API_URL}/users/${id}`);
+    if (!response.ok) return undefined;
+    return await response.json();
+  } catch (error) {
+    console.error("API Error (getUserById):", error);
+    return undefined;
+  }
+};
+
+export const getAttendanceById = async (id: string): Promise<Attendance | undefined> => {
+  try {
+    const response = await fetch(`${API_URL}/attendances/${id}`);
+    if (!response.ok) return undefined;
+    return await response.json();
+  } catch (error) {
+    console.error("API Error (getAttendanceById):", error);
+    return undefined;
+  }
+};