feat: Expo scaffold + auth screens + core screens (#39-#46, #48)

services/auth.service.ts

@@ -0,0 +1,43 @@
+import api from './api';
+
+export interface LoginPayload {
+  tenant_slug: string;
+  username: string;
+  password: string;
+}
+
+export interface LoginResponse {
+  token: string;
+  user: {
+    id: number;
+    name: string;
+    username: string;
+    email: string;
+    role: string;
+    tenant_slug: string;
+  };
+}
+
+export const authService = {
+  async checkTenantExists(slug: string): Promise<boolean> {
+    const res = await api.get(`/api/v1/auth/tenant/${slug}/exists`);
+    return res.data?.exists === true;
+  },
+
+  async login(payload: LoginPayload): Promise<LoginResponse> {
+    const res = await api.post('/api/v1/auth/login', payload);
+    return res.data;
+  },
+
+  async getProfile(): Promise<LoginResponse['user']> {
+    const res = await api.get('/api/v1/auth/me');
+    return res.data;
+  },
+
+  async changePassword(currentPassword: string, newPassword: string): Promise<void> {
+    await api.post('/api/v1/auth/change-password', {
+      current_password: currentPassword,
+      new_password: newPassword,
+    });
+  },
+};