feat(everything): add tool-level annotations to get-annotated-message

Add readOnlyHint, destructiveHint, idempotentHint, and openWorldHint
annotations to the tool config. Update docs to reflect that this tool
now demonstrates both tool-level and content annotations.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/everything/tools/get-annotated-message.ts

@@ -21,6 +21,12 @@ const config = {
   description:
     "Demonstrates how annotations can be used to provide metadata about content.",
   inputSchema: GetAnnotatedMessageSchema,
+  annotations: {
+    readOnlyHint: true,       // This tool only returns data, no side effects
+    destructiveHint: false,   // Does not delete or modify anything
+    idempotentHint: true,     // Same input always produces same output
+    openWorldHint: false,     // Does not interact with external systems
+  },
 };
 
 /**