/setspawn does not persist for very long

CMDBOOK-2117 - Reported by River.Marmorstein

Issue: I am using /setspawn and it is not working. After A While it will reset the spawn to a random place, from the spawn i have set. Other times you spawn i have spawned in rock and in other odd spots.

首先重现 /setspawn 的行为，并跟踪该命令的 spawn 持久化和 respawn 处理。确认已配置的 spawn 会持续生效，并且玩家不会被传送到随机位置或受阻位置。

由索引模型根据 Issue 内容生成。