Add secure username/password login portal

Gate the suite behind a self-contained login (no external IdP):

- User model with bcrypt-hashed passwords; admin/user roles
- /api/auth endpoints: login, logout, me, change-password, and
  admin-only user management (list/create/delete/reset/enable)
- Stateless JWT session in an HttpOnly, SameSite=Lax, auto-Secure
  cookie; middleware refuses every /api data route without a session
- login.html + auth-guard.js: login page and per-page guard with a
  top-right "name / Admin / Sign out" pill
- Admin Console now gated on admin role (passphrase gate removed) with
  a User administration card
- manage_users.py CLI to bootstrap the first admin
- Rebuilt help.js into a searchable, multi-topic help center
- Local-dev convenience: app serves html/ so the site + API share one
  origin under uvicorn (inactive in the prod container)
- Docs/env: AUTH_SECRET_KEY, requirements (bcrypt, PyJWT), README

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

server/README.md

@@ -13,7 +13,14 @@ browser → NGINX ──serves──> static site (index.html, …)
 
 | Method | Path | Purpose |
 |--------|------|---------|
-| GET  | `/api/health` | liveness check |
+| GET  | `/api/health` | liveness check (unauthenticated) |
+| POST | `/api/auth/login` | sign in (`{username, password}`) — sets the session cookie |
+| POST | `/api/auth/logout` | clear the session cookie |
+| GET  | `/api/auth/me` | the logged-in user |
+| POST | `/api/auth/password` | change your own password |
+| GET  | `/api/auth/users` | list accounts (**admin**) |
+| POST | `/api/auth/users` | create an account (**admin**) |
+| DELETE | `/api/auth/users/{id}` | delete an account (**admin**) |
 | POST | `/api/sops` | create/update a SOP (upsert by `id`) |
 | GET  | `/api/sops` | list SOP summaries |
 | GET  | `/api/sops/latest?complete=true` | most recent (complete) SOP |
@@ -33,6 +40,53 @@ fields (name, number, status, …) are promoted to columns for listing/filtering
 
 ---
 
+## Login portal (user accounts)
+
+The suite is gated by a username/password login. Sign-in issues a signed JWT
+that rides in an **HttpOnly, SameSite=Lax** cookie (`wp_session`); the cookie is
+marked **Secure** automatically whenever the request arrives over HTTPS (via
+NGINX's `X-Forwarded-Proto`). There is no server-side session store — each
+request is validated by checking the cookie's signature and expiry.
+
+**The real security boundary is the API:** every `/api/` data route is refused
+with `401` unless a valid session cookie is present (see `auth_gate` in
+`app.py`). The static pages additionally include `auth-guard.js`, which redirects
+to `login.html` when there's no session — that's for UX, not protection.
+
+Passwords are stored only as **bcrypt** hashes (`server/auth.py`). Roles are
+`admin` (may manage users) and `user`.
+
+### Set the signing secret
+
+Add `AUTH_SECRET_KEY` to `.env` (see `.env.example`). **Required in production** —
+without it the API uses a random per-process key, so logins reset on restart.
+
+```bash
+python -c "import secrets; print(secrets.token_urlsafe(48))"
+```
+
+### Create the first admin
+
+The `/api/auth/users` endpoint needs an existing admin, so bootstrap one from a
+shell (run from the **project root**, like uvicorn):
+
+```bash
+python -m server.manage_users create-admin alice --name "Alice Smith"
+# prompts for a password (min 8 chars)
+```
+
+In Docker:
+
+```bash
+docker compose exec api python -m server.manage_users create-admin alice --name "Alice Smith"
+```
+
+Other commands: `create <user> --role user`, `list`, `reset-password <user>`,
+`disable <user>`, `enable <user>`. After that, admins can add users through the
+API (or you can keep using the CLI).
+
+---
+
 ## Local dev
 
 ```bash
@@ -237,14 +291,23 @@ docker compose down -v
 
 ## Quick test
 
-```bash
-curl -X POST http://127.0.0.1:8000/api/comments \
-  -H 'Content-Type: application/json' \
-  -d '{"type":"home_feedback","name":"Test","text":"hello"}'
+`/api/health` is open; data routes now require a session, so log in first and
+reuse the cookie jar:
 
-curl http://127.0.0.1:8000/api/comments
+```bash
+curl http://127.0.0.1:8000/api/health          # {"ok":true} — no auth needed
+
+# Sign in, saving the session cookie to a jar
+curl -c jar.txt -X POST http://127.0.0.1:8000/api/auth/login \
+  -H 'Content-Type: application/json' \
+  -d '{"username":"alice","password":"<password>"}'
+
+# Reuse the cookie on protected routes
+curl -b jar.txt http://127.0.0.1:8000/api/comments
 ```
 
+Without the cookie, protected routes return `401 {"detail":"Not authenticated"}`.
+
 Or via the nginx proxy (replace with your hostname):
 
 ```bash