The endpoint used to write the client-supplied step verbatim, so a stale or
replayed request with tutorial_step=0 against any later-stage viewer would
regress the persisted state to 0. NextSceneSwitcher routes step==0 to
AreaSelect section 0, which has no chapter data — the client LINQ-Single()
crashes on next /load/index, bricking the viewer. Math.Max-preserve matches
the 31→41 pattern in GiftController.TutorialGiftReceive.
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
POST /tutorial/update echoes tutorial_step back and saves it to
Viewer.MissionData.TutorialState. is_skip=1 is handled server-side
by honoring whatever tutorial_step value the client sends (client
already sends 100 when skipping). Adds TutorialUpdateRequest DTO,
TutorialUpdateResponse DTO, injects SVSimDbContext into
TutorialController, and adds GetViewerTutorialStateAsync helper to
SVSimTestFactory.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Returns an empty data object (result_code=1 from middleware envelope).
Client uses SkipAllNetworkChecks so the response body is never read.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
