Add persistent local music catalog

apps/apple/VelodyiPhone/Sources/iPhoneLibraryViewModel.swift

@@ -11,25 +11,38 @@ final class iPhoneLibraryViewModel {
     var tracks: [LibraryTrack] = []
     var syncStatus = "Offline library not synced yet"
 
-    private let store = InMemoryLocalLibraryStore()
+    private let store: any LocalLibraryStore
     private let syncCoordinator: PlaceholderSyncCoordinator
     private var hasLoaded = false
 
     init() {
+        let repository = Self.makeTrackRepository()
         let environment = ServerEnvironment(
             baseURL: ServerEnvironment.defaultLocalBaseURL,
             appVersion: "0.1.0"
         )
         let apiClient = StubVelodyAPIClient(environment: environment)
+        self.store = repository
         self.syncCoordinator = PlaceholderSyncCoordinator(
             apiClient: apiClient,
-            store: store
+            store: repository
         )
     }
 
     func loadIfNeeded() async {
         guard !hasLoaded else { return }
         hasLoaded = true
+
+        do {
+            let persistedTracks = try await store.loadTracks()
+            if !persistedTracks.isEmpty {
+                tracks = persistedTracks
+                syncStatus = "Loaded \(persistedTracks.count) cached track(s) from local storage."
+            }
+        } catch {
+            syncStatus = "Failed to load cached catalog: \(error.localizedDescription)"
+        }
+
         await refreshSync()
     }
 
@@ -42,4 +55,12 @@ final class iPhoneLibraryViewModel {
             syncStatus = "Sync placeholder failed: \(error.localizedDescription)"
         }
     }
+
+    private static func makeTrackRepository() -> any TrackRepository {
+        if let repository = try? SwiftDataTrackRepository() {
+            return repository
+        }
+
+        return InMemoryTrackRepository()
+    }
 }