Fix upload size limit: add BODY_SIZE_LIMIT env and error handling

- Added BODY_SIZE_LIMIT=52428800 (50MB) to .env.example
- handleError in hooks catches body size exceeded and returns friendly message
- Client-side file size check on image upload input (alerts before submit)
- adapter-node uses BODY_SIZE_LIMIT env var (default was 512KB)

To fix: add BODY_SIZE_LIMIT=52428800 to .env on the server and restart.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src/hooks.server.ts

@@ -1,6 +1,20 @@
-import type { Handle } from '@sveltejs/kit';
+import type { Handle, HandleServerError } from '@sveltejs/kit';
 import { validateSession, setSessionCookie, deleteSessionCookie } from '$lib/server/auth/index.js';
 
+export const handleError: HandleServerError = async ({ error }) => {
+	const message = error instanceof Error ? error.message : 'Unknown error';
+
+	// Body size limit exceeded
+	if (message.includes('exceeds limit')) {
+		return {
+			message: 'File too large. Maximum upload size is 50MB.'
+		};
+	}
+
+	console.error('Unhandled error:', error);
+	return { message: 'An unexpected error occurred.' };
+};
+
 export const handle: Handle = async ({ event, resolve }) => {
 	const token = event.cookies.get('session');