fix: eliminate volume spikes on song transitions (#109)

Author: sozercan

Views/macOS/MiniPlayerWebView.swift

@@ -438,6 +438,17 @@ final class SingletonPlayerWebView {
                         video.volume = \(savedVolume);
                     }
 
+                    // Sync YouTube's internal player APIs to prevent overrides
+                    const ytVolume = Math.round(\(savedVolume) * 100);
+                    const player = document.querySelector('ytmusic-player');
+                    if (player && player.playerApi) {
+                        player.playerApi.setVolume(ytVolume);
+                    }
+                    const moviePlayer = document.getElementById('movie_player');
+                    if (moviePlayer && moviePlayer.setVolume) {
+                        moviePlayer.setVolume(ytVolume);
+                    }
+
                     // Clear flag after a moment
                     setTimeout(() => { window.__kasetIsSettingVolume = false; }, 100);
 

Views/macOS/SingletonPlayerWebView+ObserverScript.swift

@@ -58,6 +58,9 @@ extension SingletonPlayerWebView {
 
                     video.addEventListener('play', startPolling);
                     video.addEventListener('playing', startPolling);
+                    // Enforce volume on playing event to catch all track changes
+                    // (auto-advance, SPA navigation, button clicks)
+                    video.addEventListener('playing', () => enforceVolumeNow());
                     video.addEventListener('pause', stopPolling);
                     video.addEventListener('ended', stopPolling);
                     video.addEventListener('waiting', () => sendUpdate()); // Buffer state