Add DataContent.Name property (#6616)

* Add DataContent.Name property

Enables a name (e.g. file name) to optionally be associated with a DataContent. DataContent is often used to represent named entities, such as when uploading files.

Author: stephentoub

src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/AIAnnotation.cs

@@ -183,6 +183,13 @@ public string Uri
     [JsonIgnore]
     public string MediaType { get; }
 
+    /// <summary>Gets or sets an optional name associated with the data.</summary>
+    /// <remarks>
+    /// A service might use this name as part of citations or to help infer the type of data
+    /// being represented based on a file extension.
+    /// </remarks>
+    public string? Name { get; set; }
+
     /// <summary>Gets the data represented by this instance.</summary>
     /// <remarks>
     /// If the instance was constructed from a <see cref="ReadOnlyMemory{Byte}"/>, this property returns that data.

src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/AIAnnotationExtensions.cs

@@ -1349,6 +1349,10 @@
           "Member": "System.ReadOnlyMemory<byte> Microsoft.Extensions.AI.DataContent.Data { get; }",
           "Stage": "Stable"
         },
+        {
+          "Member": "string? Microsoft.Extensions.AI.DataContent.Name { get; set; }",
+          "Stage": "Stable"
+        },
         {
           "Member": "string Microsoft.Extensions.AI.DataContent.MediaType { get; }",
           "Stage": "Stable"

src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/AIAnnotationKind.cs

@@ -264,7 +264,7 @@ private static List<ChatMessageContentPart> ToOpenAIChatContent(IList<AIContent>
                 break;
 
             case DataContent dataContent when dataContent.MediaType.StartsWith("application/pdf", StringComparison.OrdinalIgnoreCase):
-                return ChatMessageContentPart.CreateFilePart(BinaryData.FromBytes(dataContent.Data), dataContent.MediaType, $"{Guid.NewGuid():N}.pdf");
+                return ChatMessageContentPart.CreateFilePart(BinaryData.FromBytes(dataContent.Data), dataContent.MediaType, dataContent.Name ?? $"{Guid.NewGuid():N}.pdf");
 
             case AIContent when content.RawRepresentation is ChatMessageContentPart rawContentPart:
                 return rawContentPart;

src/Libraries/Microsoft.Extensions.AI.Abstractions/Contents/AIAnnotationReference.cs

@@ -639,7 +639,7 @@ private static List<ResponseContentPart> ToOpenAIResponsesContent(IList<AIConten
                     break;
 
                 case DataContent dataContent when dataContent.MediaType.StartsWith("application/pdf", StringComparison.OrdinalIgnoreCase):
-                    parts.Add(ResponseContentPart.CreateInputFilePart(BinaryData.FromBytes(dataContent.Data), dataContent.MediaType, $"{Guid.NewGuid():N}.pdf"));
+                    parts.Add(ResponseContentPart.CreateInputFilePart(BinaryData.FromBytes(dataContent.Data), dataContent.MediaType, dataContent.Name ?? $"{Guid.NewGuid():N}.pdf"));
                     break;
 
                 case ErrorContent errorContent when errorContent.ErrorCode == nameof(ResponseContentPartKind.Refusal):