Widget v2 glassmorphism, lyrics, backup, crossfade fixes

Widget v2:
- Glassmorphism glass panel, 40-bar waveform Canvas with SeekToIntent
- CIAreaAverage color extraction + secondary color for adaptive theming
- Small: inset glass. Medium/Large: flush edge-to-edge (contentMarginsDisabled)
- Large: 3-item queue with real cover art thumbnails, crossfade countdown
- Waveform sampled from offline vis buffer, seeded PRNG fallback

Live Lyrics:
- LyricsService: direct LRCLIB from iOS, no companion dependency
- Embedded lyrics read via AVAsset.load(.metadata) from downloads
- Karaoke word-by-word gradient fill, auto-scroll, fade edges
- Tap-to-sync timing editor with +/-0.1s offset adjust
- Companion API fallback only for server-side embedded tags

Backup System:
- .nvdbackup export/import via ZIPFoundation
- UTI registered for AirDrop, passwords stripped on export
- PendingOperationsQueue with retry + disk persistence

Crossfade fixes:
- Seek bar: reports from incoming player immediately, not at 50%
- songHandoff at midpoint: art/colors/text/lyrics transition mid-fade
- Scrobble fires before metadata swap (correct outgoing song)

Visualizer fixes:
- stopAll() zeros _audioLevels + clears offlineVisBuffer
- All 5 simulation start sites gated behind realAudioAnalysis check
- Bars stay flat between skips, only rise when real vis data loads

Smart DJ bulk prefetch, appendingPathComponent slash fix

Shared/Audio/AudioPlayer.swift

@@ -293,9 +293,10 @@ class AudioPlayer: NSObject, ObservableObject {
 
         if isUsingOfflineVis {
             startOfflineVisSync()
-        } else if !isUsingCrossfade {
+        } else if !isUsingCrossfade && !VisualizerSettings.shared.realAudioAnalysis {
             startLevelSimulation()
         }
+        // When realAudioAnalysis is on but vis data hasn't loaded yet: stay at 0.
         alog("Foreground: session reactivated, observers + vis timers resumed (crossfade=\(isUsingCrossfade) offlineVis=\(isUsingOfflineVis))")
     }
 
@@ -475,7 +476,9 @@ class AudioPlayer: NSObject, ObservableObject {
                 
                 updateNowPlayingInfo()
                 fetchAndSetArtwork(coverArtId: song.coverArt)
-                startLevelSimulation()
+                if !VisualizerSettings.shared.realAudioAnalysis {
+                    startLevelSimulation()
+                }
                 
                 // Load offline visualizer for crossfade path too
                 if VisualizerSettings.shared.realAudioAnalysis {
@@ -867,9 +870,12 @@ class AudioPlayer: NSObject, ObservableObject {
         #if os(iOS)
         if isRadioStream {
             startRadioSimulation()
-        } else {
+        } else if !VisualizerSettings.shared.realAudioAnalysis {
+            // Simulation mode only — real analysis waits for offline vis data
             startLevelSimulation()
         }
+        // When realAudioAnalysis is on: levels stay at 0 until
+        // loadOfflineVisualizer → startOfflineVisSync fills them.
         #else
         startLevelSimulation()
         #endif
@@ -1090,7 +1096,7 @@ class AudioPlayer: NSObject, ObservableObject {
                 guard let self = self else { return }
                 self.setLevels(self.rawFFTLevels)
             }
-        } else {
+        } else if !VisualizerSettings.shared.realAudioAnalysis {
             DebugLogger.shared.log("resume: simulation path — levelTimer nil=\(levelTimer == nil)", category: "VisDebug")
             // Simulation path: seed internalLevels from a fresh random target
             // so the wave has height immediately rather than starting from floor.
@@ -1100,6 +1106,7 @@ class AudioPlayer: NSObject, ObservableObject {
             setLevels(internalLevels)
             if levelTimer == nil { startLevelSimulation() }
         }
+        // else: realAudioAnalysis on, vis data loading — stay at 0
         pushWidgetState()
         #endif
         updateNowPlayingInfo()
@@ -1626,7 +1633,7 @@ class AudioPlayer: NSObject, ObservableObject {
                     }
                 } catch {
                     alog("Offline vis: analysis failed: \(error.localizedDescription)")
-                    await MainActor.run { self.startLevelSimulation() }
+                    // Don't fall back to simulation — levels stay at 0
                 }
                 } // end if !fetched
             }