LDEV-5643 LDEV-5881 switch to using Java 25 ScopedValues

[zspitzer]

https://luceeserver.atlassian.net/browse/LDEV-5881
https://luceeserver.atlassian.net/browse/LDEV-5643

[zspitzer]

re: Removal of InheritableThreadLocal

Support During the migration from ThreadLocal to ScopedValue, the pcThreadLocalInheritable (InheritableThreadLocal) was removed because ScopedValue does not support automatic inheritance to child threads like InheritableThreadLocal did.

The INHERIT_ENABLED flag was set to false, and inheritance functionality was intentionally disabled. As part of the performance optimization cleanup, we removed the now-dead "pc from parent thread" code blocks that were checking pcThreadLocalInheritable.get() - these blocks had been reduced to pc = null;

if (pc != null) after the variable was removed, making them unreachable dead code. Child threads that need access to a parent's PageContext must now explicitly pass it or establish a new ScopedValue scope using ScopedValue.where(ThreadLocalPageContext.CURRENT, pc).call(() -> {}). This is a more explicit and safer pattern for virtual threads.