Add waveform profile HTTP transport: API endpoint, public proxy, content client method

DeepDrftPublic.Client/Clients/TrackMediaClient.cs

@@ -1,3 +1,6 @@
+using System.Net;
+using System.Net.Http.Json;
+using DeepDrftModels.DTOs;
 using Microsoft.Extensions.DependencyInjection;
 using NetBlocks.Models;
 
@@ -61,4 +64,36 @@ public class TrackMediaClient
             return ApiResult<TrackMediaResponse>.CreateFailResult(e.Message);
         }
     }
+
+    /// <summary>
+    /// Fetches a track's stored waveform loudness profile. A 404 means no profile is stored
+    /// (existing tracks predate profiling, or computation failed at upload); callers treat that
+    /// as "render a flat seekbar" rather than an error, so it surfaces as a fail result with a
+    /// stable message rather than throwing.
+    /// </summary>
+    public async Task<ApiResult<WaveformProfileDto>> GetWaveformProfileAsync(string trackId, CancellationToken cancellationToken = default)
+    {
+        try
+        {
+            var response = await _http.GetAsync($"api/track/{trackId}/waveform", cancellationToken);
+            if (response.StatusCode == HttpStatusCode.NotFound)
+            {
+                return ApiResult<WaveformProfileDto>.CreateFailResult("No waveform profile available");
+            }
+
+            response.EnsureSuccessStatusCode();
+
+            var profile = await response.Content.ReadFromJsonAsync<WaveformProfileDto>();
+            if (profile is null)
+            {
+                return ApiResult<WaveformProfileDto>.CreateFailResult("Waveform profile response was empty");
+            }
+
+            return ApiResult<WaveformProfileDto>.CreatePassResult(profile);
+        }
+        catch (Exception e)
+        {
+            return ApiResult<WaveformProfileDto>.CreateFailResult(e.Message);
+        }
+    }
 }