feat(vereinfacht): member form flash and show page

- Form: show Vereinfacht sync warning after save via SyncFlash
- Show: load API debug response; MembershipFees: contact ID, link, no-contact warning

lib/mv_web/live/member_live/show.ex

@@ -256,6 +256,7 @@ defmodule MvWeb.MemberLive.Show do
           id={"membership-fees-#{@member.id}"}
           member={@member}
           current_user={@current_user}
+          vereinfacht_debug_response={@vereinfacht_debug_response}
         />
       <% end %>
     </Layouts.app>
@@ -264,7 +265,10 @@ defmodule MvWeb.MemberLive.Show do
 
   @impl true
   def mount(_params, _session, socket) do
-    {:ok, assign(socket, :active_tab, :contact)}
+    {:ok,
+     socket
+     |> assign(:active_tab, :contact)
+     |> assign(:vereinfacht_debug_response, nil)}
   end
 
   @impl true
@@ -316,6 +320,16 @@ defmodule MvWeb.MemberLive.Show do
     {:noreply, assign(socket, :active_tab, :membership_fees)}
   end
 
+  def handle_event("load_vereinfacht_debug", %{"contact_id" => contact_id}, socket) do
+    response =
+      case Mv.Vereinfacht.Client.get_contact(contact_id) do
+        {:ok, body} -> {:ok, body}
+        {:error, reason} -> {:error, reason}
+      end
+
+    {:noreply, assign(socket, :vereinfacht_debug_response, response)}
+  end
+
   # Flash set in LiveComponent is not shown in parent layout; child sends this to display flash
   @impl true
   def handle_info({:put_flash, type, message}, socket) do