Fix: Ensure POST requests always send body content to Jellyfin

- Always send body content for POST requests, even if empty (send '{}')
- Update TODO.md to mark tasks 2 and 3 as done
- Improve logging for POST body debugging

allstarr/Services/Jellyfin/JellyfinProxyService.cs

@@ -256,15 +256,14 @@ public class JellyfinProxyService
         
         using var request = new HttpRequestMessage(HttpMethod.Post, url);
         
-        // Create content from body string
+        // Create content from body string - ALWAYS set content even if empty
-        if (!string.IsNullOrEmpty(body))
+        // Jellyfin expects a body for POST requests, even if it's "{}"
+        var bodyToSend = string.IsNullOrWhiteSpace(body) ? "{}" : body;
+        request.Content = new StringContent(bodyToSend, System.Text.Encoding.UTF8, "application/json");
+        
+        if (string.IsNullOrWhiteSpace(body))
         {
-            request.Content = new StringContent(body, System.Text.Encoding.UTF8, "application/json");
+            _logger.LogWarning("POST body was empty for {Url}, sending empty JSON object", url);
-            _logger.LogDebug("POST body length: {Length} bytes", body.Length);
-        }
-        else
-        {
-            _logger.LogWarning("POST body is empty for {Url}", url);
         }
         
         bool authHeaderAdded = false;
@@ -312,12 +311,12 @@ public class JellyfinProxyService
         }
         else
         {
-            _logger.LogInformation("POST to Jellyfin: {Url}, body length: {Length} bytes", url, body.Length);
+            _logger.LogInformation("POST to Jellyfin: {Url}, body length: {Length} bytes", url, bodyToSend.Length);
             
             // Log body content for playback endpoints to debug
             if (endpoint.Contains("Playing", StringComparison.OrdinalIgnoreCase))
             {
-                _logger.LogInformation("Sending body to Jellyfin: {Body}", body);
+                _logger.LogInformation("Sending body to Jellyfin: {Body}", bodyToSend);
             }
         }