feat(video-assets): add full video asset system (uploads, downloads, @mentions, and cleanup/billing integration)

components/video-page/image-upload-utils.ts

@@ -0,0 +1,29 @@
+'use client';
+
+export const MAX_IMAGE_UPLOAD_BYTES = 10 * 1024 * 1024;
+
+export function validateImageFile(file: File): string | null {
+  if (!file.type.startsWith('image/')) {
+    return 'Please select an image file';
+  }
+
+  if (file.size > MAX_IMAGE_UPLOAD_BYTES) {
+    return 'Image must be less than 10MB';
+  }
+
+  return null;
+}
+
+export function extractPastedImageFile(data: DataTransfer | null | undefined): File | null {
+  const items = data?.items;
+  if (!items) return null;
+
+  for (let i = 0; i < items.length; i++) {
+    const item = items[i];
+    if (!item.type.startsWith('image/')) continue;
+    const file = item.getAsFile();
+    if (file) return file;
+  }
+
+  return null;
+}