raise upload size cap to ~1.86 GB and nginx timeouts to 1200s

Raise RequestSizeLimit/MultipartBodyLengthLimit on upload+replace-audio,
MaxUploadBytes in BatchUpload/BatchEdit, and DefaultResponseTimeoutSeconds to
1200s. Add client_max_body_size 2000m and proxy_read/send_timeout 1200s to the
nginx manager/public confs.

DeepDrftManager/Services/CmsTrackService.cs

@@ -28,11 +28,11 @@ public class CmsTrackService : ICmsTrackService
     private const int DefaultIdleTimeoutSeconds = 90;
 
     // Response-wait budget: once the request body is fully on the wire the server runs AudioProcessor
-    // decode → vault write → SQL persist. For a several-hundred-MB WAV this can take many minutes.
+    // decode → vault write → SQL persist. For a multi-GB WAV this can exceed 10 minutes.
     // The idle heartbeat goes silent after the last byte, so a separate, larger deadline governs the
     // response-wait phase so a fully-uploaded file is never killed mid-persist.
     // Operator-tunable via Upload:ResponseTimeoutSeconds.
-    private const int DefaultResponseTimeoutSeconds = 600; // 10 minutes
+    private const int DefaultResponseTimeoutSeconds = 1200; // 20 minutes
 
     private readonly IHttpClientFactory _httpClientFactory;
     private readonly ILogger<CmsTrackService> _logger;