feat: put invite links on hold; single brand header everywhere

feat: CAML lab branding - CCR logo, ink+teal theme, favicon, attribution

refactor: enhance AdminPage overview display and improve navigation

Refactor admin page to include collapsible sections and enhance invite link management

Four-tier access model: self-governing admin, pre-login access, audit trail

Admin: no password reset for Google accounts (UI + backend guard)

Admin page v1: user roles (lab tier), password resets, failed-run requeue, verification queue