Fix curves in extended negative world heights

[twme-ai]

Overview

Fixes #3606

Description

LocalBlockVectorSet.wrapped() is designed to upgrade to BlockVectorSet when a position falls outside its local coordinate range. However, its add(BlockVector3) overload delegated directly to the underlying set and bypassed the upgrade logic in add(int, int, int). EditSession#drawSpline uses the vector overload, causing curves below the vanilla world height to throw an IndexOutOfBoundsException.

This delegates vector additions through the upgrade-aware overload and adds regression coverage for the coordinates reported in the issue, including preservation of entries added before an upgrade.

Testing

• ./gradlew :worldedit-core:test --tests com.fastasyncworldedit.core.math.LocalBlockVectorSetTest --rerun-tasks --no-daemon --no-configure-on-demand
• ./gradlew :worldedit-core:build --no-daemon --no-configure-on-demand

Submitter Checklist

• Make sure you are opening from a topic branch (/feature/fix/docs/ branch (right side)) and not your main branch.
• Ensure that the pull request title represents the desired changelog entry.
• New public fields and methods are annotated with @since TODO. No public API was added.
• I read and followed the contribution guidelines.