A GitHub project checked out only on another of the person's hosts showed as `ace2 · natembp` on Nate16, and every channel creation entry point was missing or disabled there. The person expected one ace2 project across machines and chose to set up a checkout on Nate16 and run channels there, with a default folder they can change.

**Expected** - A GitHub-backed project shows its ordinary name (ace2) in the picker and All Projects regardless of which host has a checkout. Folders without a GitHub remote keep host disambiguation; a channel's host stays independent. - A GitHub project without a checkout on this machine offers **Set up on this Mac**. New channel / + (Channels sidebar, All Projects per-project +, dashboard, GitHub **Open in a channel**) reaches setup instead of being hidden. Selecting a project never clones. - Setup shows an editable destination, `~/code/<repo>` by default, before cloning. The host clones asynchronously, expands `~`, normalizes the path, and registers the checkout through the existing project-open machinery. An existing matching checkout is opened; other non-empty folders are refused; failures stay in the form with the path preserved; Ace never deletes a partial clone. - A creation that led to setup continues locally with its initial dashboard or GitHub text; drafts survive until admission. Standalone setup only adds the project. Nothing is created or run on the other machine. - Cloning must not depend on gh's authenticated GraphQL lookup: on Nate16, `gh repo clone githubnext/ace2` is refused by organization SAML SSO applied to the gh token even though ace2 is public, while anonymous `git ls-remote https://github.com/githubnext/ace2.git` works. A plain `git clone` of the validated `https://github.com/<owner>/<repo>.git` works for public repositories and uses existing Git credential helpers only when the server requires authentication.

Part of #15; follows #157, which merged repository identity but deliberately creates only from this host's checkout. Dogfooding gap from #5.