feat(pagination): 공통 컨트롤 도입과 사용자 관리 가이드 추가

- 테이블 푸터에서 SuperportPaginationControls를 사용하도록 각 관리 페이지 페이지네이션 로직을 정리

- SuperportPaginationControls 위젯을 추가하고 SuperportTable 푸터를 개선해 페이지 사이즈 선택과 이동 버튼을 분리

- 사용자 등록·계정 관리 요구사항을 문서화한 doc/user_setting.md를 작성하고 AGENTS.md 코멘트 규칙을 업데이트

- flutter analyze를 수행해 빌드 경고가 없음을 확인

lib/features/masters/product/presentation/pages/product_page.dart

@@ -7,6 +7,7 @@ import 'package:superport_v2/core/constants/app_sections.dart';
 import 'package:superport_v2/widgets/app_layout.dart';
 import 'package:superport_v2/widgets/components/filter_bar.dart';
 import 'package:superport_v2/widgets/components/superport_dialog.dart';
+import 'package:superport_v2/widgets/components/superport_pagination_controls.dart';
 import 'package:superport_v2/widgets/components/superport_table.dart';
 import 'package:superport_v2/widgets/components/responsive_section.dart';
 
@@ -157,9 +158,6 @@ class _ProductEnabledPageState extends State<_ProductEnabledPage> {
         final totalPages = result == null || result.pageSize == 0
             ? 1
             : (result.total / result.pageSize).ceil().clamp(1, 9999);
-        final hasNext = result == null
-            ? false
-            : (result.page * result.pageSize) < result.total;
 
         final showReset =
             _searchController.text.isNotEmpty ||
@@ -324,34 +322,11 @@ class _ProductEnabledPageState extends State<_ProductEnabledPage> {
                   alignment: WrapAlignment.end,
                   runAlignment: WrapAlignment.end,
                   children: [
-                    ShadButton.outline(
-                      size: ShadButtonSize.sm,
-                      onPressed: _controller.isLoading || currentPage <= 1
-                          ? null
-                          : () => _goToPage(1),
-                      child: const Text('처음'),
-                    ),
-                    ShadButton.outline(
-                      size: ShadButtonSize.sm,
-                      onPressed: _controller.isLoading || currentPage <= 1
-                          ? null
-                          : () => _goToPage(currentPage - 1),
-                      child: const Text('이전'),
-                    ),
-                    ShadButton.outline(
-                      size: ShadButtonSize.sm,
-                      onPressed: _controller.isLoading || !hasNext
-                          ? null
-                          : () => _goToPage(currentPage + 1),
-                      child: const Text('다음'),
-                    ),
-                    ShadButton.outline(
-                      size: ShadButtonSize.sm,
-                      onPressed:
-                          _controller.isLoading || currentPage >= totalPages
-                          ? null
-                          : () => _goToPage(totalPages),
-                      child: const Text('마지막'),
+                    SuperportPaginationControls(
+                      currentPage: currentPage,
+                      totalPages: totalPages,
+                      isBusy: _controller.isLoading,
+                      onPageSelected: _goToPage,
                     ),
                   ],
                 ),