Refactor Next.js configuration and remove Sentry integration

- Updated `serverExternalPackages` in the Next.js configuration to exclude `@sentry/node`, improving compatibility with React's RSC/client boundary.
- Removed the `instrumentation.ts` file and refactored Sentry-related code to a no-op, ensuring it does not interfere with the Next.js build process.
- Simplified the dashboard page by integrating `DashboardGuildGrid`, enhancing the user interface and reducing complexity in the component structure.

apps/webui/next.config.ts

@@ -5,9 +5,7 @@ const nextConfig: NextConfig = {
   output: 'standalone',
   transpilePackages: ['@nexumi/shared'],
   outputFileTracingRoot: path.join(__dirname, '../..'),
-  // Keep Node-only packages out of the Next server webpack bundle so they
-  // cannot break React's RSC/client boundary during page-data collection.
-  serverExternalPackages: ['@sentry/node', '@prisma/client', 'ioredis', 'bullmq']
+  serverExternalPackages: ['@prisma/client', 'ioredis', 'bullmq']
 };
 
 export default nextConfig;