feat: Add FFmpeg audio transcoding for Dolby/AC3/EAC3 compatibility

- Add /api/transcode endpoint for audio-only transcoding
- Video passthrough (no re-encoding) for fast performance
- Audio transcode to AAC for browser compatibility
- Add 'Force Audio Transcode' setting toggle in UI
- Add ffmpeg-static as optional dependency
- Handle Electron asar.unpacked path for packaged apps

public/js/pages/Settings.js

@@ -29,6 +29,7 @@ class SettingsPage {
         const rememberVolumeToggle = document.getElementById('setting-remember-volume');
         const autoPlayNextToggle = document.getElementById('setting-autoplay-next');
         const forceProxyToggle = document.getElementById('setting-force-proxy');
+        const forceTranscodeToggle = document.getElementById('setting-force-transcode');
 
         // Load current settings
         if (this.app.player?.settings) {
@@ -41,6 +42,9 @@ class SettingsPage {
             if (forceProxyToggle) {
                 forceProxyToggle.checked = this.app.player.settings.forceProxy || false;
             }
+            if (forceTranscodeToggle) {
+                forceTranscodeToggle.checked = this.app.player.settings.forceTranscode || false;
+            }
         }
 
         // Arrow keys toggle
@@ -83,6 +87,12 @@ class SettingsPage {
             this.app.player.saveSettings();
         });
 
+        // Force transcode toggle
+        forceTranscodeToggle?.addEventListener('change', () => {
+            this.app.player.settings.forceTranscode = forceTranscodeToggle.checked;
+            this.app.player.saveSettings();
+        });
+
         // EPG refresh interval
         const epgRefreshSelect = document.getElementById('epg-refresh-interval');
         if (epgRefreshSelect) {