fix: avoid concurrent command tree rebuilds

[Missdrop]

Problem

[16:08:03] [Paper Async Command Builder Thread Pool - 3/ERROR]: Caught previously unhandled exception in Paper Async Command Builder Thread Pool - 3
java.util.ConcurrentModificationException
	at java.base/java.util.LinkedHashMap$LinkedHashIterator.nextNode(LinkedHashMap.java:1024) ~[?:?]
	at java.base/java.util.LinkedHashMap$LinkedEntryIterator.next(LinkedHashMap.java:1059) ~[?:?]
	at java.base/java.util.LinkedHashMap$LinkedEntryIterator.next(LinkedHashMap.java:1056) ~[?:?]
	at java.base/java.util.AbstractMap.hashCode(AbstractMap.java:499) ~[?:?]
	at com.mojang.brigadier.tree.CommandNode.hashCode(CommandNode.java:145) ~[purpur-26.3.jar:26.3-2642-0b28be2]
	at java.base/java.util.HashMap.hash(HashMap.java:338) ~[?:?]
	at java.base/java.util.HashMap.put(HashMap.java:619) ~[?:?]
	at net.minecraft.commands.Commands.sendAsync(Commands.java:521) ~[purpur-26.3.jar:26.3-2642-0b28be2]
	at net.minecraft.commands.Commands.lambda$sendCommands$0(Commands.java:503) ~[purpur-26.3.jar:26.3-2642-0b28be2]
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1090) ~[?:?]
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:614) ~[?:?]
	at java.base/java.lang.Thread.run(Thread.java:1474) ~[?:?]
[16:08:03] [Paper Async Command Builder Thread Pool - 2/ERROR]: Caught previously unhandled exception in Paper Async Command Builder Thread Pool - 2
java.util.ConcurrentModificationException
	at java.base/java.util.LinkedHashMap$LinkedHashIterator.nextNode(LinkedHashMap.java:1024) ~[?:?]
	at java.base/java.util.LinkedHashMap$LinkedEntryIterator.next(LinkedHashMap.java:1059) ~[?:?]
	at java.base/java.util.LinkedHashMap$LinkedEntryIterator.next(LinkedHashMap.java:1056) ~[?:?]
	at java.base/java.util.AbstractMap.hashCode(AbstractMap.java:499) ~[?:?]
	at com.mojang.brigadier.tree.CommandNode.hashCode(CommandNode.java:145) ~[purpur-26.3.jar:26.3-2642-0b28be2]
	at java.base/java.util.HashMap.hash(HashMap.java:338) ~[?:?]
	at java.base/java.util.HashMap.put(HashMap.java:619) ~[?:?]
	at net.minecraft.commands.Commands.sendAsync(Commands.java:521) ~[purpur-26.3.jar:26.3-2642-0b28be2]
	at net.minecraft.commands.Commands.lambda$sendCommands$0(Commands.java:503) ~[purpur-26.3.jar:26.3-2642-0b28be2]
	at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1090) ~[?:?]
	at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:614) ~[?:?]
	at java.base/java.lang.Thread.run(Thread.java:1474) ~[?:?]

Summary

• Skip dynamic command re-registration when the configuration has not changed.
• Remove per-player updateCommands() calls that conflict with Paper's async command builder.
• Fix ConcurrentModificationException when running /trmenu reload.