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/SimpleMediaTypeRegistryTests.cs

@@ -485,13 +485,15 @@ public class SimpleMediaTypeRegistryTests
         }
 
         [Test]
-        public async Task CreateVaultAsync_MediaVaultType_ReturnsNull()
+        public async Task CreateVaultAsync_MediaVaultType_CreatesMediaFileVault()
         {
             // Act
             var vault = await Registry.CreateVaultAsync(MediaVaultType.Media, TestDirectory);
 
-            // Assert
-            Assert.That(vault, Is.Null, "Should return null for unsupported Media vault type");
+            // Assert — Media now has a concrete vault (MediaFileVault) for plain MediaBinary
+            // sidecars such as waveform loudness profiles.
+            Assert.That(vault, Is.Not.Null);
+            Assert.That(vault, Is.InstanceOf<MediaFileVault>());
         }
     }