Enrich Amazon album track durations via search results

media_from_asin returns no duration data. get_album_tracks now does one
search_raw call using the album name + primary artist from stream tags,
filters hits by albumAsin == requested asin, and builds a duration_map
(track asin → duration_ms). Search failures are swallowed — duration_ms
falls back to 0 so the existing behaviour is preserved on error.

2 new tests: duration populated when search returns matching hit; duration
stays 0 when search endpoint returns an error.

core/amazon_client.py

@@ -501,12 +501,28 @@ class AmazonClient:
             streams = self.media_from_asin(asin)
         except AmazonClientError:
             return None
+
+        # media_from_asin has no duration — enrich from search results which do.
+        duration_map: Dict[str, int] = {}  # track asin → duration_ms
+        if streams:
+            album_name = _strip_edition(streams[0].album)
+            artist_name = _primary_artist(streams[0].artist)
+            try:
+                search_items = self.search_raw(
+                    f"{album_name} {artist_name}", types="track,album"
+                )
+                for item in search_items:
+                    if item.album_asin == asin and item.duration_seconds:
+                        duration_map[item.asin] = item.duration_seconds * 1000
+            except Exception:
+                pass
+
         items = [
             {
                 "id": s.asin,
                 "name": _strip_edition(s.title),
                 "artists": [{"name": _primary_artist(s.artist), "id": ""}],
-                "duration_ms": 0,
+                "duration_ms": duration_map.get(s.asin, 0),
                 "track_number": s.track_number,
                 "disc_number": s.disc_number,
                 "release_date": s.date or "",

tests/tools/test_amazon_client.py

@@ -844,6 +844,30 @@ class TestGetAlbumTracks:
         assert item["track_number"] == 3
         assert item["disc_number"] == 1
 
+    def test_duration_enriched_from_search(self):
+        search_resp = {
+            "results": [{"hits": [
+                {"document": {
+                    "asin": "B09XYZ1234", "__type": "track",
+                    "title": "Not Like Us", "artistName": "Kendrick Lamar",
+                    "albumAsin": "B09XYZ1234", "duration": 217,
+                }},
+            ]}]
+        }
+        client = _make_client({
+            "amazon-music/media-from-asin": [MEDIA_RESPONSE_FLAC],
+            "amazon-music/search": search_resp,
+        })
+        with patch("core.amazon_client._rate_limit"):
+            result = client.get_album_tracks("B09XYZ1234")
+        assert result["items"][0]["duration_ms"] == 217_000
+
+    def test_duration_zero_when_search_fails(self):
+        client = _make_client({"amazon-music/media-from-asin": [MEDIA_RESPONSE_FLAC]})
+        with patch("core.amazon_client._rate_limit"):
+            result = client.get_album_tracks("B09XYZ1234")
+        assert result["items"][0]["duration_ms"] == 0
+
     def test_returns_none_on_api_error(self):
         client = _make_client()
         client.session.get.return_value = _mock_response({}, 500)