fix(catalog): show a new album once in Recently Added, not once per track

Recently Added listed every newly-added track individually, so importing a
14-track album filled the whole row with that one album and buried everything
else. Both code paths that build the row had the same symptom from separate
causes:

- Online: Jellyfin's /Items/Latest defaults to GroupItems=false, returning each
  new leaf on its own. Send GroupItems=true so the server collapses children
  into the container that was added.
- Offline: the downloaded-items CTE deliberately matches leaves *and* their
  container (right for browsing, wrong here), so a downloaded album returned the
  album plus each of its tracks. Drop a leaf only when its own container is in
  the same result.

Items with no container (movies, standalone tracks) are unaffected in both
paths. The online URL is extracted into build_latest_items_endpoint so it can be
asserted without an HTTP server, matching build_favorites_endpoint.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

src-tauri/src/repository/offline.rs

@@ -1426,6 +1426,14 @@ impl MediaRepository for OfflineRepository {
                 FROM items i
                  INNER JOIN downloaded_items di ON i.id = di.id
                  WHERE i.server_id = ? AND i.library_id = ?
+                 -- Collapse leaves into the container that was added: a new
+                 -- 14-track album should read as one album, not 14 songs. Only
+                 -- drops a leaf when its own container is present in the same
+                 -- result, so a standalone track or movie still appears.
+                 AND NOT EXISTS (
+                     SELECT 1 FROM downloaded_items parent
+                     WHERE parent.id IN (i.album_id, i.season_id, i.series_id, i.parent_id)
+                 )
                  ORDER BY i.synced_at DESC
                  LIMIT {}", limit_val
             ),
@@ -3544,6 +3552,32 @@ mod tests {
         .unwrap();
     }
 
+    /// Like `insert_item`, but sets `library_id` — which `get_latest_items`
+    /// filters on, so rows without it are invisible to that query.
+    async fn insert_library_item(
+        db: &Arc<RusqliteService>,
+        id: &str,
+        item_type: &str,
+        library_id: &str,
+        album_id: Option<&str>,
+    ) {
+        db.execute(Query::with_params(
+            "INSERT INTO items (id, server_id, library_id, name, item_type, album_id, synced_at)
+             VALUES (?1, 'test-server', ?2, ?3, ?4, ?5, '2024-01-01')",
+            vec![
+                QueryParam::String(id.to_string()),
+                QueryParam::String(library_id.to_string()),
+                QueryParam::String(format!("Name {id}")),
+                QueryParam::String(item_type.to_string()),
+                album_id
+                    .map(|s| QueryParam::String(s.to_string()))
+                    .unwrap_or(QueryParam::Null),
+            ],
+        ))
+        .await
+        .unwrap();
+    }
+
     async fn seed_completed_download(db: &Arc<RusqliteService>, item_id: &str, file_size: i64) {
         db.execute(Query::with_params(
             "INSERT INTO downloads (item_id, status, file_size) VALUES (?1, 'completed', ?2)",
@@ -3578,6 +3612,36 @@ mod tests {
         )
     }
 
+    /// A newly-synced album appears once in "recently added", not once per track.
+    ///
+    /// The downloaded-items CTE deliberately matches both the leaves and their
+    /// container, which is right for browsing but wrong here: it made a 3-track
+    /// album occupy 4 slots in the row. Tracks whose album is itself in the
+    /// result are now collapsed into it.
+    #[tokio::test]
+    async fn test_get_latest_items_collapses_tracks_into_their_album() {
+        let db = create_test_db();
+        insert_library_item(&db, "album-1", "MusicAlbum", "lib-1", None).await;
+        for track in ["track-1", "track-2", "track-3"] {
+            insert_library_item(&db, track, "Audio", "lib-1", Some("album-1")).await;
+            seed_completed_download(&db, track, 1000).await;
+        }
+        // A movie has no container, so it must still show up on its own.
+        insert_library_item(&db, "movie-1", "Movie", "lib-1", None).await;
+        seed_completed_download(&db, "movie-1", 2000).await;
+
+        let repo = make_repo(&db);
+        let latest = repo.get_latest_items("lib-1", Some(16)).await.unwrap();
+        let ids: Vec<&str> = latest.iter().map(|i| i.id.as_str()).collect();
+
+        assert!(
+            !ids.iter().any(|id| id.starts_with("track-")),
+            "individual tracks must collapse into their album, got: {ids:?}"
+        );
+        assert!(ids.contains(&"album-1"), "the album itself is listed");
+        assert!(ids.contains(&"movie-1"), "containerless items still listed");
+    }
+
     /// UT: downloaded-only browse returns a downloaded leaf AND its container,
     /// filtered to the requested album parent. A non-downloaded sibling is omitted.
     ///