Align attachment video detection with server

Co-Authored-By: Paperclip <noreply@paperclip.ing>

ui/src/components/IssueAttachmentsSection.test.tsx

@@ -207,6 +207,35 @@ describe("IssueAttachmentsSection", () => {
     expect(fetchSpy).not.toHaveBeenCalled();
   });
 
+  it("does not promote specific non-video content types by filename alone", async () => {
+    const attachment = makeAttachment({
+      id: "zip-mp4",
+      originalFilename: "bundle.mp4",
+      contentType: "application/zip",
+      contentPath: "/api/attachments/zip-mp4/content",
+      openPath: "/api/attachments/zip-mp4/content",
+      downloadPath: "/api/attachments/zip-mp4/content?download=1",
+    });
+
+    await act(async () => {
+      root.render(
+        <QueryClientProvider client={queryClient}>
+          <IssueAttachmentsSection
+            attachments={[attachment]}
+            onDelete={vi.fn()}
+            onImageClick={vi.fn()}
+          />
+        </QueryClientProvider>,
+      );
+    });
+    await flushReact();
+
+    expect(container.querySelector("video")).toBeNull();
+    expect(container.textContent).toContain("bundle.mp4");
+    expect(container.textContent).toContain("application/zip");
+    expect(fetchSpy).not.toHaveBeenCalled();
+  });
+
   it("keeps generic attachments as compact file rows with open and download actions", async () => {
     const attachment = makeAttachment({
       id: "pdf-attachment",

ui/src/lib/issue-attachments.ts

@@ -1,6 +1,12 @@
 import type { IssueAttachment } from "@paperclipai/shared";
 import { isVideoContentType } from "./issue-output";
 
+const GENERIC_ATTACHMENT_CONTENT_TYPES = new Set([
+  "application/octet-stream",
+  "binary/octet-stream",
+  "application/x-binary",
+]);
+
 function normalizedContentType(attachment: Pick<IssueAttachment, "contentType">) {
   return attachment.contentType.toLowerCase().split(";")[0]?.trim() ?? "";
 }
@@ -28,7 +34,9 @@ export function isImageAttachment(attachment: Pick<IssueAttachment, "contentType
 export function isVideoAttachment(
   attachment: Pick<IssueAttachment, "contentType" | "originalFilename">,
 ) {
-  if (isVideoContentType(normalizedContentType(attachment))) return true;
+  const contentType = normalizedContentType(attachment);
+  if (isVideoContentType(contentType)) return true;
+  if (!GENERIC_ATTACHMENT_CONTENT_TYPES.has(contentType)) return false;
 
   const filename = (attachment.originalFilename ?? "").toLowerCase();
   return (