feature: a minimal implementation of the appointment feature done.

frontend/src/lib/api/appointments.ts

@@ -0,0 +1,32 @@
+import { apiClient } from './client';
+import type { AppointmentColumnProvider, AppointmentRecord } from '@/types/appointment';
+
+export interface CreateAppointmentBody {
+  patientId: string;
+  providerUserId: string;
+  startAt: string;
+  endAt: string;
+  purpose: string;
+}
+
+export const appointmentsApi = {
+  columnProviders: async (): Promise<{ success: boolean; data: AppointmentColumnProvider[] }> => {
+    const response = await apiClient.get('/appointments/column-providers');
+    return response.data;
+  },
+
+  list: async (params: { from: string; to: string }): Promise<{ success: boolean; data: AppointmentRecord[] }> => {
+    const response = await apiClient.get('/appointments', { params });
+    return response.data;
+  },
+
+  create: async (body: CreateAppointmentBody): Promise<{ success: boolean; data: AppointmentRecord }> => {
+    const response = await apiClient.post('/appointments', body);
+    return response.data;
+  },
+
+  remove: async (id: string): Promise<{ success: boolean }> => {
+    const response = await apiClient.delete(`/appointments/${id}`);
+    return response.data;
+  },
+};