feat: add custom footer configuration via /footer (#19001)

Co-authored-by: Keith Guerin <keithguerin@gmail.com>
Co-authored-by: Jacob Richman <jacob314@gmail.com>

packages/cli/src/ui/commands/footerCommand.tsx

@@ -0,0 +1,25 @@
+/**
+ * @license
+ * Copyright 2026 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+import {
+  type SlashCommand,
+  type CommandContext,
+  type OpenCustomDialogActionReturn,
+  CommandKind,
+} from './types.js';
+import { FooterConfigDialog } from '../components/FooterConfigDialog.js';
+
+export const footerCommand: SlashCommand = {
+  name: 'footer',
+  altNames: ['statusline'],
+  description: 'Configure which items appear in the footer (statusline)',
+  kind: CommandKind.BUILT_IN,
+  autoExecute: true,
+  action: (context: CommandContext): OpenCustomDialogActionReturn => ({
+    type: 'custom_dialog',
+    component: <FooterConfigDialog onClose={context.ui.removeComponent} />,
+  }),
+};