Fixes

- fix: correctly check for properties in thaw/snow (#2976)
- Un-break for versions \<1.21.3 (#2988)
- Make property changes more robust (#2962)
- Fix direction changes for //undo (#2972)

✨ Features

- 1.21.3 (#2974)
- feat: alter clipboard thread to move all clipboard loading from main thread (#2867)
- feat: improve error handling for state property operations (#2975)
- Allow stacking by block units with //stack (#1539) (#2973)

✅ Chore

- Deduplicate adapter fields into superclass (#2967)