refactor: fix credo warnings, update gettext

lib/mv_web/live/group_live/form.ex

@@ -27,40 +27,46 @@ defmodule MvWeb.GroupLive.Form do
     action = if params["slug"], do: :update, else: :create
     resource = Mv.Membership.Group
 
-    unless can?(actor, action, resource) do
-      {:ok, redirect(socket, to: ~p"/groups")}
-    else
-      socket =
-        case params["slug"] do
-          nil ->
-            # New group
-            socket
-            |> assign(:group, nil)
-            |> assign(:page_title, gettext("Create Group"))
-            |> assign(:return_to, "index")
-
-          slug ->
-            # Edit existing group
-            case Membership.get_group_by_slug(slug, actor: actor) do
-              {:ok, nil} ->
-                socket
-                |> put_flash(:error, gettext("Group not found."))
-                |> redirect(to: ~p"/groups")
-
-              {:ok, group} ->
-                socket
-                |> assign(:group, group)
-                |> assign(:page_title, gettext("Edit Group"))
-                |> assign(:return_to, "show")
-
-              {:error, _error} ->
-                socket
-                |> put_flash(:error, gettext("Failed to load group."))
-                |> redirect(to: ~p"/groups")
-            end
-        end
-
+    if can?(actor, action, resource) do
+      socket = load_group_for_form(socket, params, actor)
       {:ok, assign_form(socket)}
+    else
+      {:ok, redirect(socket, to: ~p"/groups")}
+    end
+  end
+
+  defp load_group_for_form(socket, params, actor) do
+    case params["slug"] do
+      nil ->
+        # New group
+        socket
+        |> assign(:group, nil)
+        |> assign(:page_title, gettext("Create Group"))
+        |> assign(:return_to, "index")
+
+      slug ->
+        # Edit existing group
+        load_existing_group(socket, slug, actor)
+    end
+  end
+
+  defp load_existing_group(socket, slug, actor) do
+    case Membership.get_group_by_slug(slug, actor: actor) do
+      {:ok, nil} ->
+        socket
+        |> put_flash(:error, gettext("Group not found."))
+        |> redirect(to: ~p"/groups")
+
+      {:ok, group} ->
+        socket
+        |> assign(:group, group)
+        |> assign(:page_title, gettext("Edit Group"))
+        |> assign(:return_to, "show")
+
+      {:error, _error} ->
+        socket
+        |> put_flash(:error, gettext("Failed to load group."))
+        |> redirect(to: ~p"/groups")
     end
   end