feat(public,security,data): visitor public site + AI guide, security hardening, V42-V45 migrations
- frontend: visitor public home (AiAssistant, AiPlanningBriefing, VisitorTrackPage),
3-track public routing (PublicShell/App), i18n ko/en/zh/ja, favicon
- backend: public AI visitor-assistant + event calendar API (publicsite/*),
profile avatar API (auth/profile/*), SecurityConfig CORS whitelist,
SecretStartupValidator (B12 fail-fast, prod only), application-prod.yml,
AppIntegrity, /api/auth/me expansion (MeResponse)
- db: V42 bulk demo seed, V43 visitor_guide/transport + event calendar view,
V44 performance indexes, V45 app_user profile photo columns (all idempotent)
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>