feat(api): add typed API client, auth context, and integrate registration/login flows; docs: add backend integration guide and .env.example

src/lib/api/users.ts

@@ -0,0 +1,20 @@
+import { http } from '../http';
+import type {
+  UpdateCompanyRequest,
+  UpdateGstRegistrationRequest,
+  UpdateUserProfileRequest,
+  UpgradeMembershipRequest,
+  UserProfile,
+} from '../../types/api';
+
+export const usersApi = {
+  profile: () => http.get<UserProfile>('/users/profile'),
+  updateProfile: (payload: UpdateUserProfileRequest) => http.put<UserProfile>('/users/profile', payload),
+
+  updateCompany: (payload: UpdateCompanyRequest) => http.put<UserProfile>('/users/company', payload),
+  updateGst: (payload: UpdateGstRegistrationRequest) => http.put<UserProfile>('/users/gst-registration', payload),
+  upgradeMembership: (payload: UpgradeMembershipRequest) => http.post<UserProfile>('/users/upgrade-membership', payload),
+
+  stats: () => http.get<any>('/users/stats'),
+  membershipInfo: () => http.get<any>('/users/membership-info'),
+};