Why: R2 spans backend (migration v10, auth/session APIs, CLI user subcommands), frontend (login page, forced change gate, admin user management), documents (decision record). Evidence: make test full suite green on this head (exit 0); headless journey on the real binary with --auth on covers admin bootstrap, first-login forced change for created and reset passwords, non-admin menu gating, API-key login, logout. Impact: auth-enabled deployments gain password login and admin account management; embedded no-auth mode unchanged. Merge order: backend -> frontend -> documents -> this PR. Refs: proposal 2026-09-30-ui-redesign-and-auth.md (R2 admin-issued)
ui
@ fe31573d88