Fix Next.js 15 compatibility and TypeScript errors

- Update API route handlers to use async params for Next.js 15 compatibility
- Fix MUI DataGrid deprecated props (pageSize -> initialState.pagination)
- Replace Material-UI Grid components with Box for better compatibility
- Fix admin authentication system with proper request parameters
- Update permission constants to match available AdminPermission enum values
- Add missing properties to Page interface for type safety
- Update .gitignore to exclude venv/, import logs, and large data directories
- Optimize Next.js config to reduce memory usage during builds

🤖 Generated with [Claude Code](https://claude.ai/code)

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

app/admin/pages/page.tsx

@@ -40,6 +40,8 @@ interface Page {
   id: string;
   title: string;
   slug: string;
+  content: string;
+  contentType: 'RICH_TEXT' | 'HTML' | 'MARKDOWN';
   status: 'DRAFT' | 'PUBLISHED' | 'ARCHIVED';
   showInNavigation: boolean;
   showInFooter: boolean;
@@ -319,8 +321,13 @@ export default function PagesManagement() {
           columns={columns}
           loading={loading}
           autoHeight
-          pageSize={25}
-          disableSelectionOnClick
+          initialState={{
+            pagination: {
+              paginationModel: { pageSize: 25, page: 0 }
+            }
+          }}
+          pageSizeOptions={[25, 50, 100]}
+          disableRowSelectionOnClick
           sx={{
             '& .MuiDataGrid-cell': {
               borderBottom: '1px solid #f0f0f0'