feat(profile): resume-first update flow via extract-resume API

Move header divider below title block instead of under user bar

Add Back to app navigation from profile setup overlay

Unify app-shell UI across launcher, Search Lab, batch status, and profile setup

Harden profile UI: gate Clerk controls until loaded, safe progress chunks

Add visible Sign out during profile setup and on the main user bar

feat: Clerk multi-user profiles, browser extraction, lab sandbox, scoring overrides