backend/portal_auth.py: stdlib HMAC-signed session cookie carrying the access-
token id (re-validated against the DB each request, so revoke kills live
sessions), hash_token, resolve_token, and the get_current_client dependency
(raises PortalAuthError). SECRET_KEY env (insecure dev default + warning).
routers/portal.py: /portal/enter/{token} mints the cookie -> /portal; /logout;
/access; /portal home stub. main.py registers the router + a PortalAuthError
handler (HTML access page for pages, 401 JSON for /portal/api/*).
Portal shell templates (base, access_required, overview stub), branded dark.
Verified: cookie round-trip + tamper/garbage rejection, token resolution
(valid/bad), get_current_client (valid/no-cookie/revoked) — 8/8 against a temp DB.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
