refactor(server): enhance HTTP handler modularity and fix resource leak

- Rename customWriter struct to httpWriter for clarity
- Add closeWriter field to properly close write side of connections
- Update all cw variable references to hw
- Merge handlerTLS into handler function to reduce code duplication
- Extract handler into smaller, focused methods
- Split Read/Write/forwardRequest into composable functions

Fixes resource leak where connections weren't properly closed on the
write side, matching the forwarder's CloseWrite() pattern.

server/server.go

@@ -33,8 +33,9 @@ func New(sshConfig *ssh.ServerConfig, sessionRegistry session.Registry, grpcClie
 		log.Fatalf("failed to listen on port 2200: %v", err)
 		return nil, err
 	}
+	redirectTLS := config.Getenv("TLS_ENABLED", "false") == "true" && config.Getenv("TLS_REDIRECT", "false") == "true"
 
-	HttpServer := NewHTTPServer(sessionRegistry)
+	HttpServer := NewHTTPServer(sessionRegistry, redirectTLS)
 	err = HttpServer.ListenAndServe()
 	if err != nil {
 		log.Fatalf("failed to start http server: %v", err)