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/routes/(app)/devices/[id]/+page.svelte

@@ -139,6 +139,13 @@
 				{#if showUploadForm}
 					<form method="POST" action="?/uploadImage" enctype="multipart/form-data" use:enhance class="mb-4 flex flex-wrap items-end gap-3">
 						<input type="file" name="image" accept="image/*" required
+							onchange={(e) => {
+								const file = (e.target as HTMLInputElement).files?.[0];
+								if (file && file.size > 50 * 1024 * 1024) {
+									alert('File too large. Maximum size is 50MB.');
+									(e.target as HTMLInputElement).value = '';
+								}
+							}}
 							class="text-sm text-gray-600 dark:text-gray-400" />
 						<input type="text" name="caption" placeholder="Caption (optional)"
 							class="rounded-md border border-gray-300 px-3 py-1.5 text-sm dark:border-gray-600 dark:bg-gray-700 dark:text-white" />