chore: 清理 src 下 113 项未使用导入和死代码

删除未使用的文件（BuiltinStatusLine.tsx、4 个重复的 .ts stub）、
移除约 55 个文件中未使用的 React 导入、
清理约 50 处未使用的导入/变量/参数。
净减少 ~296 行代码，precheck 4077 测试全部通过。

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

src/interactiveHelpers.tsx

@@ -19,11 +19,7 @@ import { isSynchronizedOutputSupported } from '@anthropic/ink';
 import type { RenderOptions, Root, TextProps } from '@anthropic/ink';
 import { KeybindingSetup } from './keybindings/KeybindingProviderSetup.js';
 import { startDeferredPrefetches } from './main.js';
-import {
-  checkGate_CACHED_OR_BLOCKING,
-  initializeGrowthBook,
-  resetGrowthBook,
-} from './services/analytics/growthbook.js';
+import { initializeGrowthBook, resetGrowthBook } from './services/analytics/growthbook.js';
 import { isQualifiedForGrove } from './services/api/grove.js';
 import { handleMcpjsonServerApprovals } from './services/mcpServerApproval.js';
 import { AppStateProvider } from './state/AppState.js';