v0.62.2: cheaper editor address advisory

A patch that takes the per-open cost out of the editor's address-collision advisory.

The edit-load advisory now checks the published corpus only. It fires when an entry you are editing collides with one already published on main, and it no longer reads sibling cairn/<concept>/<id> branches when an editor opens an entry, so opening the editor adds no GitHub reads (it previously did one branch listing plus one read per open draft). The publish-time re-check is unchanged: it stays full cross-branch and still emits publish.address_collision when a publish overrides another entry's address.

No consumer action is required, and no public export changed.