refactor(auth): drop /dashboard, land on /consume after login
Removes the starter-kit dashboard route and page; OAuth callback now
redirects to /consume, which is the real product landing under
WindowLayout. Welcome and the legacy AppSidebar/AppHeader nav helpers
swap dashboard() -> consume(). Renames DashboardTest -> ConsumeTest to
keep the guests-redirected-to-login coverage on a real auth-gated route.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>