fix(sso): preserve admin-assigned roles across SSO sign-in (#1862)

* fix(sso): preserve admin-assigned roles across SSO sign-in

An SSO/OIDC/LDAP user's role was overwritten by the IdP-derived role on
every sign-in, so a role an admin assigned in Settings > Users reverted to
the provider default on the next login. Gate role re-sync behind an opt-in
sso_role_sync setting (default off), so manual role edits persist unless the
operator explicitly enables IdP-authoritative sync. Email continues to sync
unconditionally.

Adds human-session-only GET/PUT /api/sso/config/role-sync endpoints with a
hub-side API-token rejection in the remote proxy, a frontend toggle, a
regenerated SSO settings screenshot, and matching docs.

Closes #1851

* fix(sso): satisfy CodeQL on role-sync log and test token hashing

Route three inline API-token creation blocks through the shared
createTestApiToken helper so the sha256 hashing lives in one place, and
log the role-sync toggle as a word instead of a raw boolean. No behavior
change; resolves the CodeQL js/insecure-hashing and log-injection alerts.

* fix(sso): harden role-sync gate, name the toggle, fix screenshot

Addresses pre-merge review findings on the SSO role-sync feature:
- Make the hub-side SSO config authz guard case-insensitive to match
  Express routing semantics, closing a case-variant API-token bypass.
- Give the IdP role-sync switch an accessible name.
- Capture the SSO settings screenshot at desktop size with the scroll
  area expanded so the role-sync control is fully visible.

backend/src/proxy/remoteNodeProxy.ts

@@ -50,6 +50,7 @@ import {
 } from '../middleware/permissions';
 import type { PermissionAction } from '../middleware/permissions';
 import { SETTING_WRITE_PERMISSIONS } from '../routes/settings';
+import { rejectApiTokenScope } from '../middleware/apiTokenScope';
 
 /**
  * Per-request hop timing for the critical hydration GETs, kept off the Request
@@ -378,6 +379,18 @@ export function createRemoteProxyMiddleware(): RequestHandler {
       return;
     }
 
+    // SSO configuration routes are human-session-only. The destination-side
+    // rejectApiTokenScope cannot detect the original API token because this
+    // proxy replaces incoming credentials with a node-to-node JWT. Reject
+    // API-token-authenticated requests here, covering the /sso/config collection
+    // and all descendant paths (req.path is post-/api strip). Express matches
+    // routes case-insensitively, so this guard must too (the i flag).
+    if (/^\/sso\/config(?:\/|$)/i.test(req.path)) {
+      if (rejectApiTokenScope(req, res, 'API tokens cannot access SSO configuration.')) {
+        return;
+      }
+    }
+
     const node = NodeRegistry.getInstance().getNode(req.nodeId);
     if (!node || node.type !== 'remote') {
       next();