docs(auth): document token authentication flow

documentation/TABLEOFCONTENTS.md

@@ -5,6 +5,7 @@
 ## Authentication & Users
 - **Plex OAuth, JWT sessions, RBAC** → [backend/services/auth.md](backend/services/auth.md)
 - **Local admin authentication, password change** → [backend/services/auth.md](backend/services/auth.md)
+- **Admin-generated login token per user (URL-login)** → [backend/services/auth.md](backend/services/auth.md)
 - **Route protection, auth guards** → [frontend/routing-auth.md](frontend/routing-auth.md)
 - **Login page UI/UX** → [frontend/pages/login.md](frontend/pages/login.md)
 

documentation/backend/services/auth.md

@@ -249,6 +249,13 @@ oidc.admin_claim_value       = 'readmeabook-admin'
 - **Admin Settings:** OIDC section in `/admin/settings` (auth tab)
 - **Library:** `openid-client` (OIDC discovery, token exchange, PKCE)
 
+## Admin-Generated Login Token
+
+- Login token stored as SHA-256 hash in `User.loginTokenHash`
+- Admin generates/revokes via user permissions modal
+- User login with token `/auth/token/login?token=rmab_...`
+- Invalid token redirects to `/login`
+
 ## Security
 
 - Never log tokens