Add server-side waveform loudness profiling on track upload

ILoudnessAlgorithm strategy (RmsLoudnessAlgorithm first impl), WaveformProfileService
stores quantized byte[] sidecar in new MediaFileVault (profiles vault), wired into
UnifiedTrackService.UploadAsync; failure is logged and swallowed. WaveformProfileDto
and WaveformProfileOptions in shared projects.

DeepDrftTests/MediaVaultFactoryTests.cs

@@ -71,16 +71,16 @@ public class MediaVaultFactoryTests
         }
 
         [Test]
-        public async Task From_MediaVaultType_ReturnsNull()
+        public async Task From_MediaVaultType_CreatesMediaFileVault()
         {
-            // Note: MediaVaultType.Media doesn't have a concrete vault implementation
-            // This tests the factory's handling of unsupported types
-            
+            // MediaVaultType.Media resolves to MediaFileVault — the concrete vault for plain
+            // MediaBinary entries (e.g. waveform loudness profile sidecars).
+
             // Act
             var vault = await MediaVaultFactory.From(TestDirectory, MediaVaultType.Media);
 
             // Assert
-            Assert.That(vault, Is.Null, "Should return null for unsupported Media vault type");
+            AssertVaultCreated<MediaFileVault>(vault, "Media vault creation");
         }
 
         [Test]