add hut CLI from ~xenrox as a tracked submodule (v0.8.0)

hut lives outside the ~sircmpwn umbrella but is the de-facto SourceHut
CLI, so it's worth mirroring alongside the rest. Noted in CLAUDE.md and
called out in sourcehut-refresh that the scrape won't find it — it must
be bumped manually.

init: superproject for SourceHut documentation mirror

29 upstream SourceHut repos pinned as submodules to their latest tags,
plus Claude tooling (skills, build-index script, INDEX inventory) and
phoebe-lab production patches that are not yet upstream.

Read CLAUDE.md and .claude/INDEX.md before exploring.