{{-- Web "Welcome Tour": a centered, dependency-free modal that steps through the app's main areas so a new user understands the environment. The modal stays put (it doesn't jump around); it just gently highlights the matching sidebar item for each step. Auto-offered via the dashboard welcome banner; can be relaunched from the profile (?tour=1). Marks itself done (POST onboarding.tour-done) when finished or skipped. --}}