Fix bottom border rendering for search and add a regression test.

packages/cli/GEMINI.md

@@ -15,4 +15,11 @@
 - **Utilities**: Use `renderWithProviders` and `waitFor` from
   `packages/cli/src/test-utils/`.
 - **Snapshots**: Use `toMatchSnapshot()` to verify Ink output.
+- **SVG Snapshots**: Use `await expect(renderResult).toMatchSvgSnapshot()` for
+  UI components whenever colors or detailed visual layout matter. SVG snapshots
+  capture styling accurately. Make sure to await the `waitUntilReady()` of the
+  render result before asserting. After updating SVG snapshots, always examine
+  the resulting `.svg` files (e.g. by reading their content or visually
+  inspecting them) to ensure the render and colors actually look as expected and
+  don't just contain an error message.
 - **Mocks**: Use mocks as sparingly as possible.

packages/cli/src/test-utils/render.tsx

@@ -547,6 +547,11 @@ const baseMockUiState = {
   },
   hintMode: false,
   hintBuffer: '',
+  bannerData: {
+    defaultText: '',
+    warningText: '',
+  },
+  bannerVisible: false,
 };
 
 export const mockAppState: AppState = {