v0.4.6

Fixed

• Windows client no longer disconnects every ~60 seconds. The
  client was not sending WebSocket pings, relying entirely on the
  server's pings and the auto-pong response. On Windows, power-managed
  network adapters can delay or drop a pong just long enough to trip
  the server's read timeout. Fixed by adding client-side pings every
  30 s (matching the server) and raising the server's read timeout
  from 45 s to 90 s so a single missed pong doesn't kill the
  connection.