Update tui error handling

- Allow each view to position error banners where they choose
- Add global 'esc' key handler to dismiss errors

pkg/tui/views/conversations/conversations.go

@@ -218,9 +218,13 @@ func (m *Model) Header(width int) string {
 	return styles.Header.Width(width).Render(header)
 }
 
-func (m *Model) Content(width int, height int) string {
+func (m *Model) Content(width int, height int, errors string) string {
 	m.content.Width, m.content.Height = width, height
-	return m.content.View()
+	content := m.content.View()
+	if errors != "" {
+		content += errors
+	}
+	return content
 }
 
 func (m *Model) Footer(width int) string {