- Replace self.filter with lib.fileset for more precise filtering
- Remove unnecessary clan-core dependency from the test
- Test only needs lib and pkgs, not the full flake context
- Prevents unnecessary rebuilds when unrelated files change
Some test were referring to the whole source code via ${self} which amde them rebuild on every single commit.
This is not mitigated by introduceing `self.filter { include = [...]; }` allowin to a content addressed subset of the source code in tests.
