feat: implement useUrlState hook for managing URL-based state in admin pages

- Refactor multiple admin pages (BlogsPage, ClinicsPage, DoctorsPage, etc.) to utilize the new useUrlState hook for managing pagination, search, and filter states via URL.
- Ensure that the state persists in the URL, allowing users to return to the same state when navigating back from detail pages.
- Update relevant components to handle state changes appropriately and maintain clean URLs by removing default values.
- Add SlotPicker component for selecting appointment slots based on availability.
- Create tests for useUrlState to validate its functionality and ensure correct behavior when interacting with the URL.
- Update API documentation to reflect changes in appointment creation and slot selection processes.

assets/admin/pages/ClinicsPage.tsx

@@ -14,6 +14,7 @@ import { useForm } from 'react-hook-form';
 import { zodResolver } from '@hookform/resolvers/zod';
 import { z } from 'zod';
 import { api } from '../lib/api';
+import { useUrlState, pageOf } from '../hooks/useUrlState';
 import type { ApiResponse, PaginatedResponse } from '../lib/api';
 import type { Clinic } from '../types';
 import { useAuthStore } from '../stores/authStore';
@@ -39,9 +40,14 @@ export default function ClinicsPage() {
   const qc = useQueryClient();
   const primaryRole = useAuthStore(s => s.primaryRole);
   const isRepresentation = primaryRole === 'representation';
-  const [page, setPage] = useState(1);
-  const [search, setSearch] = useState('');
-  const [statusFilter, setStatusFilter] = useState('');
+  // وضعیت لیست در URL می‌ماند تا «بازگشت» از صفحهٔ جزئیات، همین فیلترها و صفحه را برگرداند.
+  const [urlState, setUrlState] = useUrlState({ page: '1', search: '', status: '' });
+  const page = pageOf(urlState.page);
+  const search = urlState.search;
+  const statusFilter = urlState.status;
+  const setPage = (p: number) => setUrlState({ page: String(p) });
+  const setSearch = (v: string) => setUrlState({ search: v, page: '1' });
+  const setStatusFilter = (v: string) => setUrlState({ status: v, page: '1' });
   const [deleteTarget, setDeleteTarget] = useState<Clinic | null>(null);
   const [mobileTarget, setMobileTarget] = useState<{ uuid: string; name: string; mobile_number?: string | null } | null>(null);
   const [addOpen, setAddOpen] = useState(false);