Add iTunes and AcoustID as additional free music enrichment sources

- itunes.py: zero-auth fallback for album artwork when MusicBrainz/Cover Art
  Archive has no match — kicks in automatically during music enrichment,
  toggleable in Settings (on by default, no key required).
- acoustid.py: audio fingerprint identification (Chromaprint fpcalc + the
  AcoustID API) for tracks with missing/unknown artist or album — nothing
  to text-search on, so this identifies from the actual audio content
  instead. Requires a free user-supplied API key from acoustid.org/api-key,
  off by default. New /music/identify endpoint + admin trigger button.
- Dockerfile: added libchromaprint-tools for fpcalc.
- Settings page: new Music Metadata & Artwork section with both toggles.

frontend/src/pages/Settings.jsx

@@ -48,6 +48,7 @@ export default function Settings() {
     sonarr_url: "", sonarr_api_key: "",
     opensubs_api_key: "", trakt_client_id: "", trakt_client_secret: "",
     auto_transcode: "off", queue_paused: false,
+    music_itunes_fallback: true, music_acoustid_enabled: false, acoustid_api_key: "",
   });
   const [info, setInfo] = useState({});
   const [saving, setSaving] = useState(false);
@@ -58,6 +59,7 @@ export default function Settings() {
   const [pwShow, setPwShow] = useState(false);
   const [pwSaving, setPwSaving] = useState(false);
   const [enrich, setEnrich] = useState(null);
+  const [identify, setIdentify] = useState(null);
 
   const load = async () => {
     if (!isAdmin) return;
@@ -68,6 +70,9 @@ export default function Settings() {
       opensubs_api_key: data.opensubs_api_key || "",
       trakt_client_id: data.trakt_client_id || "", trakt_client_secret: data.trakt_client_secret || "",
       auto_transcode: data.auto_transcode || "off", queue_paused: !!data.queue_paused,
+      music_itunes_fallback: data.music_itunes_fallback !== false,
+      music_acoustid_enabled: !!data.music_acoustid_enabled,
+      acoustid_api_key: data.acoustid_api_key || "",
     });
     setInfo(data); setTraktStatus(ts);
   };
@@ -131,6 +136,7 @@ export default function Settings() {
   useEffect(() => {
     if (!isAdmin) return;
     api.get("/tmdb/enrich-all/status").then(({ data }) => setEnrich(data)).catch(() => {});
+    api.get("/music/identify/status").then(({ data }) => setIdentify(data)).catch(() => {});
   }, [isAdmin]);
 
   useEffect(() => {
@@ -150,6 +156,33 @@ export default function Settings() {
     return () => clearInterval(t);
   }, [enrich?.running]);
 
+  const identifyAll = async () => {
+    if (!window.confirm("Fingerprint every track with an unknown artist or album and identify it via AcoustID? This may take a while.")) return;
+    try {
+      await api.post("/music/identify");
+      const { data } = await api.get("/music/identify/status");
+      setIdentify(data);
+      toast.success("Identification started");
+    } catch (err) { toast.error(err.response?.data?.detail || "Could not start"); }
+  };
+
+  useEffect(() => {
+    if (!identify?.running) return;
+    const t = setInterval(async () => {
+      const { data } = await api.get("/music/identify/status");
+      setIdentify(data);
+      if (!data.running) {
+        clearInterval(t);
+        if (data.error) {
+          toast.error(`Identification failed: ${data.error}`);
+        } else {
+          toast.success(`Identification done — ${data.identified} of ${data.total} tracks identified`);
+        }
+      }
+    }, 2000);
+    return () => clearInterval(t);
+  }, [identify?.running]);
+
   return (
     <FieldCtx.Provider value={{ s, setS, show, setShow }}>
     <div className="min-h-screen bg-[#050505] pt-32 pb-24" data-testid="settings-page">
@@ -307,6 +340,65 @@ export default function Settings() {
             </label>
           </section>
 
+          {/* Music Metadata & Artwork */}
+          <section>
+            <h2 className="font-display text-2xl font-bold text-white mb-3">Music Metadata &amp; Artwork</h2>
+            <p className="text-sm text-[#8A8A8A] mb-4">
+              Album art/tags come from MusicBrainz + Cover Art Archive first (free, no key). These add free fallbacks for what that misses.
+            </p>
+
+            <label className="flex items-center gap-3 cursor-pointer">
+              <input
+                type="checkbox"
+                checked={s.music_itunes_fallback}
+                onChange={(e) => setS({ ...s, music_itunes_fallback: e.target.checked })}
+                className="w-4 h-4 accent-[#D9381E]"
+                data-testid="settings-itunes-fallback"
+              />
+              <span className="text-sm text-white">Fall back to iTunes Search for artwork MusicBrainz doesn't have</span>
+            </label>
+            <p className="text-xs text-[#8A8A8A] mt-1 ml-7">No API key needed — always free, no signup.</p>
+
+            <div className="mt-6 pt-6 border-t border-[#222]">
+              <div className="flex items-center justify-between mb-3">
+                <span className="text-sm text-white">AcoustID audio fingerprint identification</span>
+                <Badge on={info.acoustid_configured} />
+              </div>
+              <p className="text-sm text-[#8A8A8A] mb-4">
+                Identifies tracks with missing/unknown artist or album by fingerprinting the actual audio file — useful for badly-tagged files with nothing to text-search on. Free key at{" "}
+                <a className="text-[#D9381E]" href="https://acoustid.org/api-key" target="_blank" rel="noreferrer">acoustid.org/api-key</a>.
+              </p>
+              <label className="flex items-center gap-3 cursor-pointer mb-4">
+                <input
+                  type="checkbox"
+                  checked={s.music_acoustid_enabled}
+                  onChange={(e) => setS({ ...s, music_acoustid_enabled: e.target.checked })}
+                  className="w-4 h-4 accent-[#D9381E]"
+                  data-testid="settings-acoustid-enabled"
+                />
+                <span className="text-sm text-white">Enable AcoustID identification</span>
+              </label>
+              <Field label="API key" k="acoustid_api_key" mask />
+              {info.acoustid_configured && s.music_acoustid_enabled && (
+                <div className="mt-4 flex items-center gap-4 flex-wrap">
+                  <button type="button" onClick={identifyAll} disabled={identify?.running} className="text-xs uppercase tracking-[0.2em] border border-[#222] hover:border-[#D9381E] hover:text-[#D9381E] text-[#8A8A8A] px-4 py-2 transition-colors disabled:opacity-50" data-testid="identify-all-button">
+                    {identify?.running ? `Identifying… ${identify.done}/${identify.total}` : "Identify unknown tracks →"}
+                  </button>
+                  {identify && !identify.running && identify.error && (
+                    <span className="text-xs text-[#fca5a5]" data-testid="identify-all-error">
+                      Last run failed: {identify.error}
+                    </span>
+                  )}
+                  {identify && !identify.running && !identify.error && identify.total > 0 && (
+                    <span className="text-xs text-[#8A8A8A]" data-testid="identify-all-summary">
+                      Last run: {identify.identified} of {identify.total} identified
+                    </span>
+                  )}
+                </div>
+              )}
+            </div>
+          </section>
+
           <button type="submit" disabled={saving} className="bg-[#D9381E] hover:bg-[#ED4B32] disabled:opacity-60 text-white px-8 py-3 text-sm uppercase tracking-[0.2em]" data-testid="settings-save-button">
             {saving ? "Saving…" : "Save Settings"}
           </button>