Repo setup (Jarvus house shape)

The one-time bootstrap that turns a directory into a Jarvus repo: branches, merge policy, protection rulesets, and the Release-PR automation. Everything here is settings and plumbing — the shell that the code, the CI gates, and the release flow all sit inside.

The reason this is a skill rather than a checklist someone remembers: gh repo create ships defaults that are actively wrong for this flow, and two of the mistakes are invisible until they bite weeks later — one silently deletes your develop branch, the other lets someone squash-merge and break git branch --merged forever.

Scope: what's in, what's out