Fix CI: cpplint cleanup and create_test_request method uppercase

- src/create_test_request.cpp: uppercase method via to_upper_copy so
  create_test_request_suite/method_uppercase passes (`.method("post")`
  -> `POST`); fix cpplint header order.
- src/http_request.cpp: reorder includes to match cpplint convention
  (matching header, C system, C++ system, project) and add <utility>
  for std::move at line 363.
- examples/empty_response_example.cpp: move <microhttpd.h> before
  <memory> to satisfy cpplint header ordering.
- examples/url_registration.cpp: split a 215-char render() body to
  satisfy cpplint line-length cap (200).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: etr

examples/empty_response_example.cpp

@@ -18,9 +18,10 @@
      USA
 */
 
+#include <microhttpd.h>
+
 #include <memory>
 
-#include <microhttpd.h>
 #include <httpserver.hpp>
 
 class no_content_resource : public httpserver::http_resource {

examples/url_registration.cpp

@@ -40,7 +40,10 @@ class handling_multiple_resource : public httpserver::http_resource {
 class url_args_resource : public httpserver::http_resource {
  public:
      std::shared_ptr<httpserver::http_response> render(const httpserver::http_request& req) {
-         return std::shared_ptr<httpserver::http_response>(new httpserver::http_response(httpserver::http_response::string("ARGS: " + std::string(req.get_arg("arg1")) + " and " + std::string(req.get_arg("arg2")))));
+         std::string body = "ARGS: " + std::string(req.get_arg("arg1"))
+             + " and " + std::string(req.get_arg("arg2"));
+         return std::shared_ptr<httpserver::http_response>(
+             new httpserver::http_response(httpserver::http_response::string(body)));
      }
 };
 

src/create_test_request.cpp

@@ -20,12 +20,14 @@
 */
 
 #include "httpserver/create_test_request.hpp"
-#include "httpserver/detail/http_request_impl.hpp"
 
 #include <memory>
 #include <string>
 #include <utility>
 
+#include "httpserver/detail/http_request_impl.hpp"
+#include "httpserver/string_utilities.hpp"
+
 namespace httpserver {
 
 namespace {
@@ -50,7 +52,7 @@ http_request create_test_request::build() {
     req.impl_.reset(new detail::http_request_impl());
     req.impl_.get_deleter().fn = &delete_test_impl_heap;
 
-    req.set_method(_method);
+    req.set_method(string_utilities::to_upper_copy(_method));
     req.set_path(_path);
     req.set_version(_version);
     req.set_content(_content);

src/http_request.cpp

@@ -20,15 +20,11 @@
 */
 
 #include "httpserver/http_request.hpp"
-#include "httpserver/detail/http_request_impl.hpp"
-// TASK-016: pull in connection_state to read the per-connection arena
-// out of MHD on impl construction. Both headers are gated by
-// HTTPSERVER_COMPILATION so this stays internal.
-#include "httpserver/detail/webserver_impl.hpp"
 
 #include <inttypes.h>
 #include <stdio.h>
 #include <stdlib.h>
+
 #include <algorithm>
 #include <atomic>
 #include <iostream>
@@ -37,8 +33,14 @@
 #include <memory_resource>
 #include <string>
 #include <tuple>
+#include <utility>
 #include <vector>
 
+// TASK-016: pull in connection_state to read the per-connection arena
+// out of MHD on impl construction. Both headers are gated by
+// HTTPSERVER_COMPILATION so this stays internal.
+#include "httpserver/detail/http_request_impl.hpp"
+#include "httpserver/detail/webserver_impl.hpp"
 #include "httpserver/http_utils.hpp"
 #include "httpserver/string_utilities.hpp"