Entra ID sign-in page, filters that stick to a thread, and an agent picker

[nlundee]

Summary

Three commits on top of #68:

1. Agent picker and thread flow (9d44742)
2. Entra ID is the only login (3e71f8d)
3. Hardening after a security audit (6e80ff1)

Live: https://qa.kunnskap.digdir.cloud, which currently runs main. This branch is not deployed yet.

1. Agent picker and thread flow

The composer picks an agent rather than a raw tool, with the agent's description beside it. The agent's modes sit behind "Avansert".

The thread flow now matches the old app:

• Start screen: no input box and no filters until you press "Ny tråd". The sources panel starts closed.
• "Ny tråd" starts a new thread. Before, the turn state survived. The old answer stayed on screen, and the next question was sent into the previous conversation.
• Filters stick to a thread. The filter a thread was started with is restored, locked, when you reopen it. Follow-up questions use it.
  • The server keeps it in memory. The backend stores it with each message (message/config), but its conversation API does not return it, so this is a stopgap until it does.
• Filter boxes stay inside their column. Long names are cut short with "…", and the full name shows on hover. Picking an option clears the search text.
• Stop button: the send button becomes a stop button (■) while an answer runs.
• Repeated questions: asking the same question twice in a row no longer drops the second turn.

2. Entra ID is the only login

• Sign-in page: /auth/login shows a card with an Azure AD button instead of redirecting straight to Microsoft. The button links to /auth/start, which starts the flow.
  • It is a link, not a form, because form-action 'self' would block a form post that redirects to Microsoft.
  • Sign-in errors show on the same card.
• Logout: the sidebar shows who is signed in and a "Logg ut" link. It ends the session, signs out of Entra ID and returns to the sign-in page.
• Supabase removed: the one-time e-mail codes were a stopgap while tenant consent was pending, and consent is granted.
  • The mode, its module and the browser session handoff are gone. AUTH_MODE is entra or off.
• Bicep: the template always deploys Entra, and a new publicHost parameter sets APP_ORIGIN and the callback for the custom domain.

3. Hardening after a security audit

Three reviewers covered auth and sessions, the request handling, and the frontend, infrastructure and branch history. They found nothing Critical or High, and no secrets in the history. This commit fixes the rest:

• Bounded filter store: it keeps only known fields as bounded lists of strings, and /api/* has a 64 KB body limit. A signed-in user could otherwise fill the container's memory through the filter field.
• No domain check in the app: who may sign in is Entra ID's decision (single tenant). The guest-UPN parsing the check relied on could be fooled, so ALLOWED_EMAIL_DOMAINS is removed.
• Fallback filter: a thread with no stored filter (after a restart, an eviction, or on another replica) uses the filter the browser sends instead of running unfiltered.
• Return paths: safeReturnTo normalises dot segments before refusing /auth/ paths.
• Cookies: session and state cookies use the __Host- prefix on https.
• No login-off in production: AUTH_MODE=off refuses to start unless APP_ORIGIN is localhost.

Deploying

• Everyone is signed out once. The session cookie is renamed.
• Old container variables: ALLOWED_EMAIL_DOMAINS, SUPABASE_URL, SUPABASE_PUBLISHABLE_KEY and the supabase-publishable-key secret are no longer read, and can be removed from the container app.
• Entra redirect URIs: the app registration now lists only https://qa.kunnskap.digdir.cloud/auth/callback, and https://qa.kunnskap.digdir.cloud/ for the logout return. Local development runs with AUTH_MODE=off.

Testing

npm run typecheck, npm test (60 server, 55 web), npm run build and az bicep build pass.

Verified locally against a local backend:

• Thread flow: new thread, filter, ask, "Ny tråd", reopen: the filter is restored and locked.
• Repeated question: the same question twice keeps both turns.
• Stop button: it cancels and shows "Avbrutt."
• Sign-in and logout: the full Entra round trip, while localhost callbacks were still registered.
• Body limit: a 100 KB request gets 413.
• Login-off guard: AUTH_MODE=off with a public APP_ORIGIN exits.