Respackopts

Commits in Release 4.9.0:
- chore: bump to 1.20.6
- feat: introduce validation layer to detect early resource loads and infinite recursion
- fix: move validation layer under debugLogs option that already exists for things like that
- chore: mention additional incompatible mods in FMJ
- chore: remove dashloader compat
- fix: use different log category for IO logs
- chore: clean up logging
- feat: rewrite pack discovery and add warnings for duplicate IDs
- chore: optimize imports
- fix: properly account for MetaCache mutation when removing old keys
- fix: avoid expensive tree equality computation when comparing pack states
- fix: don't clear cache prematurely when there are multiple pack managers