fix: define CreateMessageResultSchema locally for backwards compat

The spec's CreateMessageResult includes array content and tool types
(ToolUseContent, ToolResultContent), but the SDK's v1.x API expects
single content without tools for backwards compatibility.

- Import generated CreateMessageResultSchema as CreateMessageResultSpecSchema
- Define local CreateMessageResultSchema with single SamplingContentSchema
  (text/image/audio only, no arrays, no tool types)
- Keep CreateMessageResultWithToolsSchema for full spec-compliant responses

This fixes type errors in toolWithSampleServer.ts and spec.types.test.ts
where code expected single content blocks.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

Author: ochafik

src/types.ts

@@ -103,7 +103,7 @@ import {
     // Sampling schemas
     CreateMessageRequestParamsSchema,
     CreateMessageRequestSchema,
-    CreateMessageResultSchema,
+    CreateMessageResultSchema as CreateMessageResultSpecSchema,
     // Elicitation schemas
     ElicitRequestFormParamsSchema,
     ElicitRequestURLParamsSchema,
@@ -273,7 +273,8 @@ export {
     CompleteResultSchema,
     CreateMessageRequestParamsSchema,
     CreateMessageRequestSchema,
-    CreateMessageResultSchema,
+    // Note: CreateMessageResultSchema is defined locally for backwards compat (single content, no tools)
+    // CreateMessageResultSpecSchema (generated) is used for CreateMessageResultWithToolsSchema
     ElicitRequestFormParamsSchema,
     ElicitRequestURLParamsSchema,
     ElicitRequestParamsSchema,
@@ -595,6 +596,27 @@ export const SamplingContentSchema = z.discriminatedUnion('type', [TextContentSc
 
 // SamplingMessageSchema, CreateMessageRequestParamsSchema, CreateMessageRequestSchema,
 
+/**
+ * The client's response to a sampling/create_message request (backwards-compatible version).
+ * Uses single content block without tool types for v1.x API compatibility.
+ * For tool use support, use CreateMessageResultWithToolsSchema instead.
+ */
+export const CreateMessageResultSchema = ResultSchema.extend({
+    /**
+     * The name of the model that generated the message.
+     */
+    model: z.string(),
+    /**
+     * The reason why sampling stopped, if known.
+     */
+    stopReason: z.optional(z.enum(['endTurn', 'stopSequence', 'maxTokens']).or(z.string())),
+    role: RoleSchema,
+    /**
+     * Response content. Single block, basic types only (text/image/audio).
+     */
+    content: SamplingContentSchema
+});
+
 /**
  * The client's response to a sampling/create_message request when tools were provided.
  * This version supports array content for tool use flows.