feat(downloads): a bare link is titled once, a missing picture shows a glyph

A job with no name yet is titled by its short link, as the link itself;
the channel line no longer falls back to the ref and the link line does
not repeat it. No picture at all draws a film (or note) glyph instead of
an empty box.

frontend/src/components/downloadTitle.ts

@@ -2,6 +2,27 @@ import type { DownloadJob } from "../lib/api";
 
 // A download job's display title (a user rename wins over the extracted asset title), shared by the
 // row, the admin list and the library player. Its own module so downloadRow exports only components.
+// With no name yet — a link queued before its details arrive, or one that failed first — it is the
+// link itself, shortened the way the row shows a link, never the raw ref (a URL, or a bare video id).
 export function jobTitle(job: DownloadJob): string {
-  return job.display_name || job.asset?.title || job.source_ref;
+  return (
+    job.display_name ||
+    job.asset?.title ||
+    (job.source_url ? displayUrl(job.source_url) : job.source_ref)
+  );
+}
+
+/** The job has a name of its own (a rename or an extracted title), not the link standing in for one. */
+export function hasOwnTitle(job: DownloadJob): boolean {
+  return !!(job.display_name || job.asset?.title);
+}
+
+// Compact display of a URL: drop the protocol + trailing slash so "youtube.com/watch?v=…" fits.
+export function displayUrl(url: string): string {
+  try {
+    const u = new URL(url);
+    return (u.host + u.pathname + u.search).replace(/\/$/, "");
+  } catch {
+    return url;
+  }
 }