Normalize app UI pane packages

internal/appui/detail/model.go

@@ -0,0 +1,17 @@
+package detail
+
+type EmptyState struct {
+	Title string
+	Body  string
+}
+
+type VaultSummary struct {
+	Title   string
+	Detail  string
+	Context string
+}
+
+type AttachmentItem struct {
+	Name string
+	Size int
+}