Add OIDC login and per-domain authorization

Authentication previously implied full authorization: any valid token
could manage every host, DNS provider, domain, and user. This adds SSO
login and a per-domain rights model.

OIDC login (authorization_code + PKCE):
- conf.oidc + conf.auth blocks; clientSecret in (gitignored) secrets.js.
- utils/oidc.js (state/PKCE, code exchange, userinfo) using global fetch.
- models/oidc_state.js: short-lived state store, auto-expiring via
  model-redis 1.5 per-key TTL.
- routes/auth.js: GET /auth/oidc/start + /auth/oidc/callback; JIT-provisions
  a local user, mints an AuthToken carrying the SSO groups, hands the token to
  the browser via a URL fragment. "Log in with SSO" button on the login page.

Authorization (groups + app overrides, per-domain, with ownership):
- models/grant.js + utils/roles.js (pure, unit-tested): effective rights from
  conf.auth (admin users/groups, group->role map), Grant records
  (user|group -> global|domain -> viewer|manager|admin), and ownership
  (created_by). Roles rank admin > manager(owner) > viewer.
- AuthToken stores session groups; middleware/auth.js exposes req.groups.
- middleware/authz.js: requireAdmin, requireDomainRole(minRole, resolveDomain),
  filterViewable. Applied across routes: host mutations need manager on the
  host's domain; reads are filtered to visible domains; DNS providers, user
  management, and grant management are global-admin-only; certs need viewer.
- routes/grant.js: admin CRUD for grants. Anti-lockout via conf.auth.adminUsers
  plus migrations/grant_bootstrap.js.

Frontend: /me returns effective rights; nav gates Users/Grants to admins;
grants management page; OIDC token-fragment handling in app-base.js.

Tests: utils/roles and utils/oidc unit-tested (no redis); wired into the test
scripts. Full suite 89 pass. Also verified end-to-end against redis (grant
resolution, middleware allow/deny/403, list filtering) and the OIDC pure flow.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

nodejs/models/user_ldap.js

@@ -9,6 +9,19 @@ const client = new Client({
 });
 
 
+// Best-effort group extraction from a directory entry's `memberOf` values.
+// Turns `cn=dns-team,ou=groups,dc=...` into `dns-team`. Directories that don't
+// return memberOf simply yield no groups (see conf note); explicit group-search
+// can be added later if needed.
+const parse_groups = function(memberOf){
+	if(!memberOf) return [];
+	let values = Array.isArray(memberOf) ? memberOf : [memberOf];
+	return values.map(function(dn){
+		let match = /^cn=([^,]+)/i.exec(String(dn));
+		return match ? match[1] : String(dn);
+	});
+}
+
 const user_parse = function(data){
 	if(data[conf.userNameAttribute]){
 		data.username = data[conf.userNameAttribute]
@@ -20,6 +33,8 @@ const user_parse = function(data){
 		delete data.uidNumber;
 	}
 
+	data.groups = parse_groups(data.memberOf);
+
 	return data;
 }