Fix CI: add ChangeLog entry and missing include <utility>

Add ChangeLog entry for the binary buffer example to satisfy the
ChangeLog Check workflow. Add missing #include <utility> for
std::move to fix cpplint warning.

https://claude.ai/code/session_01S3BvBrSoNvUhpYTyhPYCjJ

Author: claude

ChangeLog

@@ -22,6 +22,8 @@ Version 0.20.0
 		websocket_handler, websocket_session, register_ws_resource().
 	Added utility functions: reason_phrase(), is_feature_supported(),
 		get_mhd_version().
+	Added example and documentation for serving binary data from memory
+		using string_response (addresses PR #368).
 	Added conditional compilation for basic auth (HAVE_BAUTH), mirroring
 		existing HAVE_DAUTH pattern for digest auth. Basic auth support
 		is auto-detected via AC_CHECK_LIB and can be disabled at build time.

examples/binary_buffer_response.cpp

@@ -32,6 +32,7 @@
 
 #include <memory>
 #include <string>
+#include <utility>
 
 #include <httpserver.hpp>