Transfer Ticket Department

Who may transfer: gated exactly like every other write on this ticket (_require_kind_grant_or_assignee, checked against the ticket's CURRENT kind, before anything moves) -- holding the current kind's grant or being its assignee. Deliberately NOT gated on also holding the DESTINATION kind's grant: a CS agent holding only tickets:b2c who transfers a ticket to b2g is pushing work into a queue they cannot see, and that is the intended shape of this feature -- an attorney's mail landing on the consumer address, or (the production shape this was built from, ticket G-59979) a government ticket whose SUBSTANCE only the consumer desk can fix, must be movable by whoever is looking at it, not gated on the mover already having a foot in the other department.

Because of that, the mover can end this call holding a ticket they can no longer open at all -- Cindy Palma, holding only tickets:b2g, transferring a b2g ticket she is assigned to (and has already replied on) over to b2c, loses _require_kind_grant_or_assignee access to it the instant this commits: her kind grant does not cover b2c, and the assignee bypass no longer applies because the transfer just cleared the assignee. still_accessible says so explicitly in the response, computed the same way that gate itself would evaluate a FRESH GET on this ticket right now -- so the caller can render "moved to the consumer queue; you no longer have access to it" instead of the ticket just disappearing from their screen with no explanation, the exact silent-disappearance pattern this build exists to avoid.