Fix compilation errors in README code samples

- Core README client sample: Use .OfType<TextContentBlock>() instead of
  .First(c => c.Type == "text").Text since ContentBlock base class lacks Text
- Core README server sample: Use McpServerOptions.ToolCollection,
  McpServer.Create(), StdioServerTransport(name), and await using
- Root README advanced server: Remove read-only Type property from
  TextContentBlock initializer
- Both IChatClient snippets: Fix trailing comma and missing closing paren

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: jeffhandley

README.md

@@ -83,7 +83,7 @@ IList<McpClientTool> tools = await client.ListToolsAsync();
 IChatClient chatClient = ...;
 var response = await chatClient.GetResponseAsync(
     "your prompt here",
-    new() { Tools = [.. tools] },
+    new() { Tools = [.. tools] });
 ```
 
 ## Getting Started (Server)
@@ -218,7 +218,7 @@ McpServerOptions options = new()
 
                 return ValueTask.FromResult(new CallToolResult
                 {
-                    Content = [new TextContentBlock { Text = $"Echo: {message}", Type = "text" }]
+                    Content = [new TextContentBlock { Text = $"Echo: {message}" }]
                 });
             }
 

src/ModelContextProtocol.Core/README.md

@@ -53,7 +53,7 @@ var result = await client.CallToolAsync(
     cancellationToken: CancellationToken.None);
 
 // echo always returns one and only one text content object
-Console.WriteLine(result.Content.First(c => c.Type == "text").Text);
+Console.WriteLine(result.Content.OfType<TextContentBlock>().First().Text);
 ```
 
 Clients can connect to any MCP server, not just ones created using this library. The protocol is designed to be server-agnostic, so you can use this library to connect to any compliant server.
@@ -68,7 +68,7 @@ IList<McpClientTool> tools = await client.ListToolsAsync();
 IChatClient chatClient = ...;
 var response = await chatClient.GetResponseAsync(
     "your prompt here",
-    new() { Tools = [.. tools] },
+    new() { Tools = [.. tools] });
 ```
 
 ## Getting Started (Server)
@@ -79,13 +79,9 @@ The core package provides the basic server functionality. Here's an example of c
 using ModelContextProtocol.Server;
 using System.ComponentModel;
 
-// Create server options
-var serverOptions = new McpServerOptions();
-
-// Add tools directly
-serverOptions.Capabilities.Tools = new()
+// Create server options with tools
+var serverOptions = new McpServerOptions
 {
-    ListChanged = true,
     ToolCollection = [
         McpServerTool.Create((string message) => $"hello {message}", new()
         {
@@ -96,9 +92,9 @@ serverOptions.Capabilities.Tools = new()
 };
 
 // Create and run server with stdio transport
-var server = new McpServer(serverOptions);
-using var stdioTransport = new StdioServerTransport();
-await server.RunAsync(stdioTransport, CancellationToken.None);
+await using var stdioTransport = new StdioServerTransport("EchoServer");
+await using var server = McpServer.Create(stdioTransport, serverOptions);
+await server.RunAsync(CancellationToken.None);
 ```
 
 For more advanced scenarios with dependency injection, hosting, and automatic tool discovery, see the `ModelContextProtocol` package.