Remote mode sets the project checkout's origin and checks it once with
git ls-remote, with no credential, no prompt, a protocol allowlist of
https and ssh and a 15 second limit. The receipt reports reachable,
needs-credential or unreachable with git's error summarized. Nothing is
pushed. URLs are https or ssh only; ext:: and other helpers, file://,
local paths, option-like values and credential-bearing URLs are refused.
`mosaic org project repo set` changes a project's repository later, both
ways between remote and local only, through the same rules and check,
with a revision guard and an org.project.repo.set receipt. The Console's
organization project Settings tab edits it through
/api/orgs/ID/repo/project/PROJECT; Quick Setup accepts ssh and shows the
check.