Persist onboardingCompleted flag server-side via /api/v1/config so the
tour only auto-starts once per DashCaddy installation, not on every
new browser that connects.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
Full codebase including API server (32 modules + routes), dashboard frontend,
DashCA certificate distribution, installer script, and deployment skills.
