Implemented the Anthropic provider (#17)

app/MindWork AI Studio/Provider/Anthropic/ChatRequest.cs

@@ -0,0 +1,19 @@
+using AIStudio.Provider.OpenAI;
+
+namespace AIStudio.Provider.Anthropic;
+
+/// <summary>
+/// The Anthropic chat request model.
+/// </summary>
+/// <param name="Model">Which model to use for chat completion.</param>
+/// <param name="Messages">The chat messages.</param>
+/// <param name="MaxTokens">The maximum number of tokens to generate.</param>
+/// <param name="Stream">Whether to stream the chat completion.</param>
+/// <param name="System">The system prompt for the chat completion.</param>
+public readonly record struct ChatRequest(
+    string Model,
+    IList<Message> Messages,
+    int MaxTokens,
+    bool Stream,
+    string System
+);