feat(WEB): 테이블 컬럼 표시/숨김 설정 기능 추가

- useColumnSettings 훅: 컬럼 가시성 토글 로직
- useTableColumnStore: Zustand 기반 컬럼 설정 영속화 (localStorage)
- ColumnSettingsPopover: 컬럼 설정 UI 컴포넌트
- UniversalListPage/IntegratedListTemplateV2에 컬럼 설정 통합

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/stores/useTableColumnStore.ts

@@ -0,0 +1,101 @@
+import { create } from 'zustand';
+import { persist } from 'zustand/middleware';
+import { safeJsonParse } from '@/lib/utils';
+
+interface PageColumnSettings {
+  columnWidths: Record<string, number>;
+  hiddenColumns: string[];
+}
+
+interface TableColumnState {
+  pageSettings: Record<string, PageColumnSettings>;
+  setColumnWidth: (pageId: string, columnKey: string, width: number) => void;
+  toggleColumnVisibility: (pageId: string, columnKey: string) => void;
+  resetPageSettings: (pageId: string) => void;
+  getPageSettings: (pageId: string) => PageColumnSettings;
+}
+
+function getUserId(): string {
+  if (typeof window === 'undefined') return 'default';
+  const userStr = localStorage.getItem('user');
+  if (!userStr) return 'default';
+  const user = safeJsonParse<Record<string, unknown> | null>(userStr, null);
+  return user?.id ? String(user.id) : 'default';
+}
+
+function getStorageKey(): string {
+  return `sam-table-columns-${getUserId()}`;
+}
+
+const DEFAULT_PAGE_SETTINGS: PageColumnSettings = {
+  columnWidths: {},
+  hiddenColumns: [],
+};
+
+export const useTableColumnStore = create<TableColumnState>()(
+  persist(
+    (set, get) => ({
+      pageSettings: {},
+
+      setColumnWidth: (pageId: string, columnKey: string, width: number) => {
+        const { pageSettings } = get();
+        const current = pageSettings[pageId] || { ...DEFAULT_PAGE_SETTINGS };
+        set({
+          pageSettings: {
+            ...pageSettings,
+            [pageId]: {
+              ...current,
+              columnWidths: { ...current.columnWidths, [columnKey]: width },
+            },
+          },
+        });
+      },
+
+      toggleColumnVisibility: (pageId: string, columnKey: string) => {
+        const { pageSettings } = get();
+        const current = pageSettings[pageId] || { ...DEFAULT_PAGE_SETTINGS };
+        const hidden = current.hiddenColumns.includes(columnKey)
+          ? current.hiddenColumns.filter((k) => k !== columnKey)
+          : [...current.hiddenColumns, columnKey];
+        set({
+          pageSettings: {
+            ...pageSettings,
+            [pageId]: { ...current, hiddenColumns: hidden },
+          },
+        });
+      },
+
+      resetPageSettings: (pageId: string) => {
+        const { pageSettings } = get();
+        const { [pageId]: _, ...rest } = pageSettings;
+        set({ pageSettings: rest });
+      },
+
+      getPageSettings: (pageId: string) => {
+        return get().pageSettings[pageId] || DEFAULT_PAGE_SETTINGS;
+      },
+    }),
+    {
+      name: 'sam-table-columns',
+      storage: {
+        getItem: (name) => {
+          const key = getStorageKey();
+          const str = localStorage.getItem(key);
+          if (!str) {
+            const fallback = localStorage.getItem(name);
+            return fallback ? JSON.parse(fallback) : null;
+          }
+          return JSON.parse(str);
+        },
+        setItem: (name, value) => {
+          const key = getStorageKey();
+          localStorage.setItem(key, JSON.stringify(value));
+        },
+        removeItem: (name) => {
+          const key = getStorageKey();
+          localStorage.removeItem(key);
+        },
+      },
+    }
+  )
+);