Add bot to play against.

internal/server/ws.go

@@ -73,6 +73,9 @@ func (s *Server) handleWS(w http.ResponseWriter, req *http.Request) {
 	r.conns[c] = struct{}{}
 	p.Connected = true
 	r.broadcastLocked()
+	// Safety net: if a scheduled bot move was ever lost (crash between
+	// persist and timer), a player connecting re-arms it.
+	s.scheduleBotsLocked(r)
 	r.mu.Unlock()
 
 	defer func() {
@@ -147,8 +150,7 @@ func (s *Server) apply(r *room, c *client, msg clientMessage) {
 		c.sendError(err.Error())
 		return
 	}
-	s.persist(r)
-	r.broadcastLocked()
+	s.commitLocked(r)
 }
 
 // broadcastLocked sends each connected client its own view of the game.