feat(ui): implement refreshed UX for Composer layout

- Promotes refreshed multi-row status area and footer as the default experience.
- Stabilizes Composer row heights to prevent layout 'jitter' during typing and model turns.
- Unifies active hook status and model loading indicators into a single, stable Row 1.
- Refactors settings to use backward-compatible 'Hide' booleans (ui.hideStatusTips, ui.hideStatusWit).
- Removes vestigial context usage bleed-through logic in minimal mode to align with global UX direction.
- Relocates toast notifications to the top status row for improved visibility.
- Updates all CLI UI snapshots and architectural tests to reflect the stabilized layout.
- Fixes persistent TypeScript compilation errors in tests by refactoring async render helpers (`LoadingIndicator.test.tsx`, `AppHeader.test.tsx`, `ToolMessage.test.tsx`) to avoid direct destructuring of complex inferred return types, ensuring consistent Promise flattening across all CI environments (Node 20/22/24).

docs/cli/tutorials/plan-mode-steering.md

@@ -5,10 +5,9 @@ structured environment with model steering's real-time feedback, you can guide
 Gemini CLI through the research and design phases to ensure the final
 implementation plan is exactly what you need.
 
-<!-- prettier-ignore -->
-> [!NOTE]
-> This is an experimental feature currently under active development and
-> may need to be enabled under `/settings`.
+> **Note:** This is a preview feature under active development. Preview features
+> may only be available in the **Preview** channel or may need to be enabled
+> under `/settings`.
 
 ## Prerequisites