feat: add user-member linking UI with autocomplete (#168)

lib/mv_web/live/user_live/index.html.heex

@@ -50,6 +50,13 @@
       {user.email}
     </:col>
     <:col :let={user} label={gettext("OIDC ID")}>{user.oidc_id}</:col>
+    <:col :let={user} label={gettext("Linked Member")}>
+      <%= if user.member do %>
+        {user.member.first_name} {user.member.last_name}
+      <% else %>
+        <span class="text-base-content/50">{gettext("No member linked")}</span>
+      <% end %>
+    </:col>
 
     <:action :let={user}>
       <div class="sr-only">