Member/Setting/validations: domain, actor, and seeds

- setting.ex: domain/authorize for default_membership_fee_type_id check
- validate_same_interval: require membership_fee_type (no None)
- set_membership_fee_start_date: domain/actor for fee type lookup
- Validations: domain/authorize for cross-resource checks
- helpers.ex, email_sync change, seeds.exs actor/authorize fixes
- Update related tests

lib/membership/setting.ex

@@ -155,12 +155,23 @@ defmodule Mv.Membership.Setting do
              on: [:create, :update]
 
     # Validate default_membership_fee_type_id exists if set
-    validate fn changeset, _context ->
+    validate fn changeset, context ->
                fee_type_id =
                  Ash.Changeset.get_attribute(changeset, :default_membership_fee_type_id)
 
                if fee_type_id do
-                 case Ash.get(Mv.MembershipFees.MembershipFeeType, fee_type_id) do
+                 # Actor may be in changeset.context (action context) or validation context
+                 ctx = changeset.context || %{}
+
+                 actor =
+                   get_in(ctx, [:private, :actor]) ||
+                     Map.get(ctx, :actor) ||
+                     (context && Map.get(context, :actor))
+
+                 # Check existence only; action is already restricted by policy (e.g. admin).
+                 opts = [domain: Mv.MembershipFees, authorize?: false]
+
+                 case Ash.get(Mv.MembershipFees.MembershipFeeType, fee_type_id, opts) do
                    {:ok, _} ->
                      :ok