feat: add autoplay suggestions when queue runs out

src/playqueue.hpp

@@ -241,6 +241,17 @@ public:
         emit queueChanged();
     }
 
+    /// Append tracks to the main queue tail (autoplay/discovery).
+    void appendToContext(const QJsonArray &tracks)
+    {
+        for (const auto &v : tracks) {
+            const QJsonObject t = v.toObject();
+            if (t["streamable"].toBool(true))
+                m_queue.append(t);
+        }
+        emit queueChanged();
+    }
+
     /// Move an upcoming item (by its index in upcomingTracks()) to the front of playNext.
     void moveUpcomingToTop(int upcomingIndex)
     {