Improve login flow a smidge by showing an error message and re-enabling the sign in button on failure

lib/dialogs/alert.rb

@@ -0,0 +1,29 @@
+module W3DHubLauncher
+  class Dialog
+    class Alert < W3DHubLauncher::Dialog
+      def setup
+        super
+
+        stack(width: 1.0, max_width: 800, height: 1.0, max_height: 480, style_class: [:dialog]) do
+          flow(width: 1.0, background_nine_slice: NINE_SLICE_ROUNDED_TOP, background_nine_slice_from_edge: NINE_SLICE_EDGE, background_nine_slice_color: 0) do
+            banner @options[:title] || "", width: 1.0, text_align: :center
+          end
+
+          stack(style_class: [:dialog_container]) do
+            tagline @options[:message] || ""
+          end
+
+          flow(width: 1.0, padding: PADDING, background_nine_slice: NINE_SLICE_ROUNDED_BOTTOM, background_nine_slice_from_edge: NINE_SLICE_EDGE, background_nine_slice_color: 0) do
+            flow(fill: true)
+
+            button "Close", **CTA_BUTTON_THEME do
+              pop_state
+            end
+
+            flow(fill: true)
+          end
+        end
+      end
+    end
+  end
+end