support image drop for upload

src/shared/utils/image-drop.ts

@@ -0,0 +1,16 @@
+import type { DragEvent } from 'react';
+
+// OS / native file drag (vs in-app library drag).
+export function isNativeFileDrag(event: DragEvent): boolean {
+    return event.dataTransfer.types.includes('Files');
+}
+
+// First file in the list whose MIME type is an image.
+export function pickFirstImageFile(files: FileList | null): File | null {
+    if (!files?.length) return null;
+    for (let i = 0; i < files.length; i++) {
+        const f = files.item(i);
+        if (f?.type.startsWith('image/')) return f;
+    }
+    return null;
+}