Make active alerts the default tab

Change the default filter from 'all' to 'active' on the alerts page.
This shows only active alerts by default, which is more useful for
monitoring current issues. Users can still click 'All Alerts' to see
the complete history.

lib/towerops_web/live/alert_live/index.ex

@@ -18,13 +18,13 @@ defmodule ToweropsWeb.AlertLive.Index do
     {:ok,
      socket
      |> assign(:page_title, "Alerts")
-     |> assign(:filter, "all")
+     |> assign(:filter, "active")
      |> load_alerts(organization.id)}
   end
 
   @impl true
   def handle_params(params, _url, socket) do
-    filter = Map.get(params, "filter", "all")
+    filter = Map.get(params, "filter", "active")
 
     {:noreply,
      socket