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.

DeepDrftAPI/Startup.cs

@@ -19,6 +19,12 @@ namespace DeepDrftAPI
             builder.Services.AddSingleton<AudioProcessor>();
             builder.Services.AddSingleton<TrackContentService>();
 
+            // Waveform loudness profiling (upload-time, off the playback path)
+            builder.Services.Configure<WaveformProfileOptions>(
+                builder.Configuration.GetSection(nameof(WaveformProfileOptions)));
+            builder.Services.AddSingleton<ILoudnessAlgorithm, RmsLoudnessAlgorithm>();
+            builder.Services.AddSingleton<WaveformProfileService>();
+
             // File Database
             var fileDatabasePath = CredentialTools.ResolvePathOrThrow("filedatabase", "environment/filedatabase.json");
             builder.Configuration.AddJsonFile(fileDatabasePath, optional: false, reloadOnChange: false);