workstation: gate t3.viktorbarzin.me to the T3 Users group (Phase 4)

New authentik_group 'T3 Users' (members wizard/emo/ancamilea via data lookups — usernames ARE their emails in this Authentik instance) + a branch in the admin-services-restriction expression policy gating t3.viktorbarzin.me to that group, placed BEFORE the ADMIN_ONLY_HOSTS early-return. Surgical two-step targeted apply (group-with-members first, then the gate) → zero lock-out window. Verified: group has all 3 members, the live policy contains the t3 branch, t3 still 302s to Authentik. Membership is HCL for now (FUTURE: roster-reconciled via the Authentik API).

Note: the authentik stack had 3 unrelated pending drift changes (pgbouncer deployment + 2 tls_secrets) — deliberately NOT applied (targeted apply isolated this change; left for the stack owner).

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

stacks/authentik/admin-services-restriction.tf

@@ -49,6 +49,12 @@ resource "authentik_policy_expression" "admin_services_restriction" {
 
     host = request.context.get("host", "")
 
+    # t3 Workstation edge gate: only members of "T3 Users" may reach t3.
+    # Placed BEFORE the ADMIN_ONLY_HOSTS early-return (t3 is intentionally not in
+    # that set — it must not require Home-Server-Admins, just T3 Users membership).
+    if host == "t3.viktorbarzin.me":
+        return ak_is_group_member(request.user, name="T3 Users")
+
     # Not an admin-only host: allow any authenticated user.
     if host not in ADMIN_ONLY_HOSTS:
         return True