Rename ArenaAllocator -> Arena

tests/test_http_handler.cpp

@@ -1,4 +1,4 @@
-#include "arena_allocator.hpp"
+#include "arena.hpp"
 #include "http_handler.hpp"
 #include "perfetto_categories.hpp"
 #include <atomic>
@@ -12,13 +12,13 @@ std::atomic<int> activeConnections{0};
 
 // Simple test helper since Connection has complex constructor requirements
 struct TestConnectionData {
-  ArenaAllocator arena;
+  Arena arena;
   std::string message_buffer;
   void *user_data = nullptr;
 
   void append_message(std::string_view data) { message_buffer += data; }
 
-  ArenaAllocator &get_arena() { return arena; }
+  Arena &get_arena() { return arena; }
   const std::string &getResponse() const { return message_buffer; }
   void clearResponse() { message_buffer.clear(); }
   void reset() {