Add `modules.zfs`, the host-level pool import: a host declares its ZFS host id
and the pools to import with their dataset mountpoints, and the module imports
those pools as durable state rather than recreating them, so a service's data
survives any rebuild or reimage.
Add a shared `storage` group with a fixed gid to the base config both the host
base and the guest-base build on, so a host and every guest carry the same
number and an identity-mapped container write lands on the pool as that group
without per-service permission juggling.
No host enables the module: the only host is a laptop with no pools and a
kernel with no ZFS build, so the enabled build was verified by ad-hoc
enablement against a ZFS-supported kernel while the committed tree stays inert.
Add modules.toolkit, an aggregator that enables fish, tmux, nvim, git,
and direnv as one unit, and makes fish the login shell, so any Host or
Guest shell feels identical. Each member is set via mkDefault, so a Host
can still override any single piece while the one flag brings up the
whole bundle.
neogaia now enables the bundle as a single line in place of its five
individual enables and its explicit default-shell line, keeping the Host
a flat checklist.
Also lands the domain model, ADR 0006, and the guests spec: the toolkit
is the first piece of the wider guests work, and the guest-base will
auto-enable this bundle.
