chore(mirror): drop sunset collaborator grant/revoke verbs

The server sunset POST/DELETE /mirrors/collaborators (grant/revoke); only the GET (list) survives. Refresh the vendored OpenAPI spec from the live core and regenerate the client — which removes the now-dead GrantMirrorCollaborator / RevokeMirrorCollaborator operations — then delete the CLI verbs that called them:

• entire repo mirror collaborators add (grant) — removed
• entire repo mirror collaborators remove (revoke) — removed
• entire repo mirror collaborators list — kept (GET still live)

The refresh also picks up three new, currently-unused server operations (deleteMe, listRepos, lookupRepoBySlug): additive generated code, no CLI surface yet.