A stable client-server connection

An update. We plow, sow, and harvest, even on weekends. An important achievement: I managed to establish a persistent two-way connection between client and server, exchange data, and, above all, process it! The connection existed before, but it didn't always do what was needed, and the implementation was awkward. Now it is stable. Every 20 seconds, client and server exchange heartbeat packets to check that both sides are alive. If things go well, I'll add database access today, and login and registration will actually work, for real. The forms and client-side logic are already ready.