WorldAccessBlocker 0.9.0

chore: bump version to 0.9.0, update CHANGELOG with real 0.8.0 history

0.8.0 already released on Modrinth — our new features go into 0.9.0.
Added full 0.8.0 changelog from Modrinth release notes.

Co-Authored-By: Claude Sonnet 4.6 noreply@anthropic.com