mcp/examples: move server example into example folder (#357)

For better organization.

examples/server/basic/main.go

@@ -0,0 +1,58 @@
+// Copyright 2025 The Go MCP SDK Authors. All rights reserved.
+// Use of this source code is governed by an MIT-style
+// license that can be found in the LICENSE file.
+
+package main
+
+import (
+	"context"
+	"fmt"
+	"log"
+
+	"github.com/modelcontextprotocol/go-sdk/mcp"
+)
+
+type SayHiParams struct {
+	Name string `json:"name"`
+}
+
+func SayHi(ctx context.Context, req *mcp.CallToolRequest, args SayHiParams) (*mcp.CallToolResult, any, error) {
+	return &mcp.CallToolResult{
+		Content: []mcp.Content{
+			&mcp.TextContent{Text: "Hi " + args.Name},
+		},
+	}, nil, nil
+}
+
+func main() {
+	ctx := context.Background()
+	clientTransport, serverTransport := mcp.NewInMemoryTransports()
+
+	server := mcp.NewServer(&mcp.Implementation{Name: "greeter", Version: "v0.0.1"}, nil)
+	mcp.AddTool(server, &mcp.Tool{Name: "greet", Description: "say hi"}, SayHi)
+
+	serverSession, err := server.Connect(ctx, serverTransport, nil)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	client := mcp.NewClient(&mcp.Implementation{Name: "client"}, nil)
+	clientSession, err := client.Connect(ctx, clientTransport, nil)
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	res, err := clientSession.CallTool(ctx, &mcp.CallToolParams{
+		Name:      "greet",
+		Arguments: map[string]any{"name": "user"},
+	})
+	if err != nil {
+		log.Fatal(err)
+	}
+	fmt.Println(res.Content[0].(*mcp.TextContent).Text)
+
+	clientSession.Close()
+	serverSession.Wait()
+
+	// Output: Hi user
+}