Adding a remote to a previously remote-less project changes its slug. Left
unhandled, the link step repinned the live memory symlink to a fresh empty
entry and orphaned the real memory.
The previous slug is read from the live symlink target rather than guessed,
which covers a remote being added, rewritten, or removed. When both the old
and new entries hold content the migration is ambiguous, so nothing moves
and the user is directed to --adopt.
rootiest
b7ff4e0981