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/api/pages/[slug]/route.ts

@@ -3,12 +3,13 @@ import { prisma } from '@/lib/db';
 
 export async function GET(
   request: NextRequest,
-  { params }: { params: { slug: string } }
+  { params }: { params: Promise<{ slug: string }> }
 ) {
   try {
+    const resolvedParams = await params;
     const page = await prisma.page.findUnique({
       where: {
-        slug: params.slug,
+        slug: resolvedParams.slug,
         status: 'PUBLISHED'
       },
       select: {