feat: filename-aware attachment download endpoint (Content-Disposition), preview download uses it (no popup flash)

app/src/lib/api.ts

@@ -147,6 +147,21 @@ export async function attachmentUploadRaw(ownerId: number, file: File, thumbB64?
   return item;
 }
 
+export async function attachmentDownload(id: number): Promise<{ blob: Blob; file_name: string; mime?: string }> {
+  const r = await fetch(getServerUrl() + '/api/attachment_download', {
+    method: 'POST',
+    headers: { 'content-type': 'application/json', authorization: 'Bearer ' + getToken() },
+    body: JSON.stringify({ id }),
+  });
+  if (!r.ok) {
+    const j = await r.json().catch(() => null);
+    throw new Error(j?.error || '下载失败');
+  }
+  const file_name = decodeURIComponent(r.headers.get('x-file-name') || (r.headers.get('content-disposition') || '').match(/UTF-8''([^;]+)/)?.[1] || 'file');
+  const mime = r.headers.get('content-type') || undefined;
+  return { blob: await r.blob(), file_name, mime };
+}
+
 export const attachmentThumb = (id: number) =>
   call<{ data_b64: string; mime?: string; file_name: string }>('attachment_thumb', { id });