GameStart already detects the Steam-vs-UDID mismatch produced by
wipe-and-resignup; it now also reclaims the orphan. New
ViewerRepository.MergeAnonymousViewerInto transfers the fresh UDID
from V_new onto V_old in one save (freeing the unique-index slot),
then deletes V_new in a second save. Partial-failure mode is a
benign null-UDID viewer; two rows never contend for the same UDID.
Side benefit: future GetViewerByUdid lookups now short-circuit to
V_old without going through the Steam handler.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
Wipe-and-resignup left the client stuck with the blank V_new's id in
Certification.ViewerId. /tool/signup is anonymous, so it can't see the
Steam ticket and creates a fresh anonymous viewer keyed on the new UDID;
the Steam handler on the next request resolves to V_old and serves its
data, but no normal-response hook overwrites Certification.ViewerId.
GameStart now compares the UDID-keyed viewer to the auth-resolved one
and emits rewrite_viewer_id when they differ, which Cute/GameStartCheckTask
writes back into Certification.ViewerId.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
