In-file comments should describe only what the file currently is, not task
numbers, external tooling, or past/future states.
- hosts/neogaia: drop the "replaced by disko" / "arrive later" framing;
describe the filesystems and hardware profile as the placeholder values
they are.
- lib: drop the "no null-placeholder traversal hack" comparison to a prior
implementation.
- system: drop "no impure environment lookup" from the user.name description
and the sops/post-boot roadmap from the user comment.