fix(clients): verify C# client, read Content-Range from content headers

clients/resolvespec-cs/src/FuncSpecClient.cs

@@ -169,7 +169,9 @@ public sealed class FuncSpecClient
         };
         if (list)
         {
-            resp.Headers.TryGetValues("Content-Range", out var cr);
+            // Content-Range is a content header in HttpClient; fall back to response headers.
+            IEnumerable<string>? cr = null;
+            if (!resp.Content.Headers.TryGetValues("Content-Range", out cr)) resp.Headers.TryGetValues("Content-Range", out cr);
             r.Metadata = MetadataFrom(cr?.FirstOrDefault(), o);
         }
         return r;

clients/resolvespec-cs/src/ResolveSpecClient.cs

@@ -28,7 +28,7 @@ public sealed class ResolveSpecClient
         _ => Convert.ToString(id, System.Globalization.CultureInfo.InvariantCulture),
     };
 
-    static string[]? BodyId(object? id) => id is IEnumerable<string> e and not string ? e.ToArray() : null;
+    static string[]? BodyId(object? id) => id is IEnumerable<string> e ? e.ToArray() : null;
 
     string Url(string schema, string entity, string? id)
     {