fix: reject timed-out block-mask parses

[twme-ai]

Summary

Reject block-mask parses that do not finish within the existing 5 ms budget.

Problem

BlockMaskBuilder.addRegex() previously ignored both timeout and interruption
from its parsing future. The method then returned a partially constructed mask
as if parsing had succeeded. In practice, an invalid //gmask input could be
reported as a successfully set global mask.

The parser now turns timeout, interruption, and unexpected worker failures
into InputParseException, cancels timed-out work, and stops the executor
immediately. Existing InputParseException failures are preserved.

Testing

env JAVA_HOME=/usr/lib/jvm/java-25-openjdk-amd64 \
  ./gradlew -Dorg.gradle.configureondemand=false \
  :worldedit-core:test \
  --tests com.fastasyncworldedit.core.function.mask.BlockMaskBuilderTest \
  --no-daemon