* fix(worktree): refuse a parent loop even when the worktree cache is cold
The parent cycle walk read each workspace's current instance from the
resolved-worktree cache, which the reparent itself invalidates, so it only
knew the two endpoints and accepted A->B->C->A. Read saved worktree
metadata instead.
* fix(worktree): fall back to locator metadata and tolerate loops saved earlier
* fix(worktree): skip another host's locator metadata in the parent loop walk
* fix(worktree): read loop-check identities from a read-only, ownership-scoped view
The per-host metadata accessor migrates a hostless legacy row into the
queried host, so the loop check could adopt another host's worktree and
refuse a valid parent. Read one read-only host snapshot instead, counting
a row only when its project is registered on that host (the resolved
list's ownership rule).
* fix: import host-qualified worktree meta helpers once
* test: match main's host-targeted lineage write contract
Brennan Benson
505d6719c0