fix: handle alert_changed PubSub messages and primary owner ordering

- Add handle_info for {:alert_changed, org_id} in AlertLive.Index and DashboardLive
  to properly handle organization-level alert change broadcasts
- Fix get_primary_owner query to prioritize is_default memberships first,
  ensuring the organization creator is always returned when multiple owners exist

Resolves 5 test failures related to PubSub message handling and
deterministic primary owner selection.

lib/towerops/organizations.ex

@@ -564,7 +564,7 @@ defmodule Towerops.Organizations do
         join: u in assoc(m, :user),
         where: m.organization_id == ^organization.id,
         where: m.role == :owner,
-        order_by: [asc: m.inserted_at],
+        order_by: [desc: m.is_default, asc: m.inserted_at, asc: m.id],
         limit: 1,
         select: u
     )

lib/towerops_web/live/alert_live/index.ex

@@ -186,6 +186,11 @@ defmodule ToweropsWeb.AlertLive.Index do
     {:noreply, load_alerts(socket, socket.assigns.current_scope.organization.id)}
   end
 
+  @impl true
+  def handle_info({:alert_changed, _org_id}, socket) do
+    {:noreply, load_alerts(socket, socket.assigns.current_scope.organization.id)}
+  end
+
   defp load_alerts(socket, organization_id) do
     all_alerts = Alerts.list_organization_alerts(organization_id, %{"limit" => 500})
 

lib/towerops_web/live/dashboard_live.ex

@@ -96,6 +96,11 @@ defmodule ToweropsWeb.DashboardLive do
     {:noreply, load_dashboard_data(socket, socket.assigns.current_scope.organization.id)}
   end
 
+  @impl true
+  def handle_info({:alert_changed, _org_id}, socket) do
+    {:noreply, load_dashboard_data(socket, socket.assigns.current_scope.organization.id)}
+  end
+
   defp load_dashboard_data(socket, organization_id) do
     organization = socket.assigns.current_scope.organization
     summary = Dashboard.get_dashboard_summary(organization_id)