A terminally deprecated method in sun.misc.Unsafe has been called

With JDK 25 we have:

```
[INFO] --- spotless:3.1.0:apply (default) @ ...
[INFO] Index file does not exist. Fallback to an empty index
WARNING: A terminally deprecated method in sun.misc.Unsafe has been called
WARNING: sun.misc.Unsafe::staticFieldBase has been called by com.diffplug.spotless.java.ModuleHelper (file:/../.m2/repository/com/diffplug/spotless/spotless-lib/4.1.0/spotless-lib-4.1.0.jar)
WARNING: Please consider reporting this to the maintainers of class com.diffplug.spotless.java.ModuleHelper
WARNING: sun.misc.Unsafe::staticFieldBase will be removed in a future release
```

JDK 25 で警告を再現し、Maven Spotless apply の出力を出発点として、spotless-lib 4.1.0 内の com.diffplug.spotless.java.ModuleHelper パスを調査します。フォーマット処理が引き続き正常に完了し、ターミナルに表示される非推奨警告が出力されなくなれば完了です。

索引モデルが issue の本文から書いたものです。