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/commands/install-github-app/ApiKeyStep.tsx

@@ -1,4 +1,4 @@
-import React, { useCallback, useState } from 'react';
+import { useCallback, useState } from 'react';
 import TextInput from '../../components/TextInput.js';
 import { useTerminalSize } from '../../hooks/useTerminalSize.js';
 import { Box, color, Text, useTheme } from '@anthropic/ink';

src/commands/install-github-app/CheckExistingSecretStep.tsx

@@ -1,4 +1,4 @@
-import React, { useCallback, useState } from 'react';
+import { useCallback, useState } from 'react';
 import TextInput from '../../components/TextInput.js';
 import { useTerminalSize } from '../../hooks/useTerminalSize.js';
 import { Box, color, Text, useTheme } from '@anthropic/ink';

src/commands/install-github-app/CheckGitHubStep.tsx

@@ -1,4 +1,3 @@
-import React from 'react';
 import { Text } from '@anthropic/ink';
 
 export function CheckGitHubStep() {

src/commands/install-github-app/ChooseRepoStep.tsx

@@ -1,4 +1,4 @@
-import React, { useCallback, useState } from 'react';
+import { useCallback, useState } from 'react';
 import TextInput from '../../components/TextInput.js';
 import { useTerminalSize } from '../../hooks/useTerminalSize.js';
 import { Box, Text } from '@anthropic/ink';

src/commands/install-github-app/CreatingStep.tsx

@@ -1,4 +1,3 @@
-import React from 'react';
 import { Box, Text } from '@anthropic/ink';
 import type { Workflow } from './types.js';
 

src/commands/install-github-app/ErrorStep.tsx

@@ -1,4 +1,3 @@
-import React from 'react';
 import { GITHUB_ACTION_SETUP_DOCS_URL } from '../../constants/github-app.js';
 import { Box, Text } from '@anthropic/ink';
 

src/commands/install-github-app/ExistingWorkflowStep.tsx

@@ -1,4 +1,3 @@
-import React from 'react';
 import { Select } from 'src/components/CustomSelect/index.js';
 import { Box, Text } from '@anthropic/ink';
 

src/commands/install-github-app/InstallAppStep.tsx

@@ -1,5 +1,4 @@
 import figures from 'figures';
-import React from 'react';
 import { GITHUB_ACTION_SETUP_DOCS_URL } from '../../constants/github-app.js';
 import { Box, Text } from '@anthropic/ink';
 import { useKeybinding } from '../../keybindings/useKeybinding.js';

src/commands/install-github-app/WarningsStep.tsx

@@ -1,5 +1,4 @@
 import figures from 'figures';
-import React from 'react';
 import { GITHUB_ACTION_SETUP_DOCS_URL } from '../../constants/github-app.js';
 import { Box, Text } from '@anthropic/ink';
 import { useKeybinding } from '../../keybindings/useKeybinding.js';