fix(gaiia): add error handling and logging for model fetch

- Handle empty manufacturer_id selection (select placeholder)
- Log and flash when model fetch fails or returns empty
- Add require Logger to reconciliation live view

lib/towerops_web/live/org/gaiia_reconciliation_live.ex

@@ -6,6 +6,8 @@ defmodule ToweropsWeb.Org.GaiiaReconciliationLive do
   alias Towerops.Gaiia.InventoryCreator
   alias Towerops.Gaiia.Reconciliation
 
+  require Logger
+
   @impl true
   def mount(_params, _session, socket) do
     org = socket.assigns.current_scope.organization
@@ -66,6 +68,10 @@ defmodule ToweropsWeb.Org.GaiiaReconciliationLive do
      |> assign(:selected_manufacturer, nil)}
   end
 
+  def handle_event("select_manufacturer", %{"manufacturer_id" => ""}, socket) do
+    {:noreply, assign(socket, :selected_manufacturer, nil)}
+  end
+
   def handle_event("select_manufacturer", %{"manufacturer_id" => manufacturer_id}, socket) do
     org_id = socket.assigns.organization.id
     existing = socket.assigns.models
@@ -75,13 +81,22 @@ defmodule ToweropsWeb.Org.GaiiaReconciliationLive do
         assign(socket, :selected_manufacturer, manufacturer_id)
       else
         case InventoryCreator.list_models(org_id, manufacturer_id) do
+          {:ok, []} ->
+            Logger.warning("Gaiia: no models for manufacturer #{manufacturer_id}")
+
+            socket
+            |> assign(:selected_manufacturer, manufacturer_id)
+            |> put_flash(:warning, t("No models found for this manufacturer."))
+
           {:ok, models} ->
             socket
             |> assign(:models, Map.put(existing, manufacturer_id, models))
             |> assign(:selected_manufacturer, manufacturer_id)
 
-          {:error, _} ->
-            socket
+          {:error, reason} ->
+            Logger.error("Gaiia: failed to fetch models: #{inspect(reason)}")
+
+            put_flash(socket, :error, t("Failed to load models. Check server logs."))
         end
       end