Fix some issues with transferring conn back to server

src/connection.hpp

@@ -323,7 +323,8 @@ private:
    * @param server Weak reference to the server for safe cleanup
    */
   Connection(struct sockaddr_storage addr, int fd, int64_t id,
-             ConnectionHandler *handler, std::weak_ptr<Server> server);
+             size_t epoll_index, ConnectionHandler *handler,
+             std::weak_ptr<Server> server);
 
   /**
    * @brief Server-only factory method for creating connections.
@@ -345,7 +346,8 @@ private:
    */
   static std::unique_ptr<Connection>
   createForServer(struct sockaddr_storage addr, int fd, int64_t id,
-                  ConnectionHandler *handler, std::weak_ptr<Server> server);
+                  size_t epoll_index, ConnectionHandler *handler,
+                  std::weak_ptr<Server> server);
 
   // Networking interface - only accessible by Server
   int readBytes(char *buf, size_t buffer_size);
@@ -357,8 +359,10 @@ private:
   int getFd() const { return fd_; }
   bool hasMessages() const { return !messages_.empty(); }
   bool shouldClose() const { return closeConnection_; }
+  size_t getEpollIndex() const { return epoll_index_; }
   const int fd_;
   const int64_t id_;
+  const size_t epoll_index_; // Index of the epoll instance this connection uses
   struct sockaddr_storage addr_; // sockaddr_storage handles IPv4/IPv6
   ArenaAllocator arena_;
   ConnectionHandler *handler_;