chore: 清理 src 下 33 项死代码和类型断言

删除未使用的文件/目录（mcp/adapter、cli/update.ts 等）、
未使用的重导出文件（design-system/color.ts 等 12 个）、
7 个零引用的导出函数、修复 5 处 as any 为精确类型。
净减少 ~1194 行代码，precheck 4077 测试全部通过。

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

src/migrations/migrateAutoUpdatesToSettings.ts

@@ -1,61 +0,0 @@
-import { logEvent } from 'src/services/analytics/index.js'
-import { getGlobalConfig, saveGlobalConfig } from '../utils/config.js'
-import { logError } from '../utils/log.js'
-import {
-  getSettingsForSource,
-  updateSettingsForSource,
-} from '../utils/settings/settings.js'
-/**
- * Migration: Move user-set autoUpdates preference to settings.json env var
- * Only migrates if user explicitly disabled auto-updates (not for protection)
- * This preserves user intent while allowing native installations to auto-update
- */
-export function migrateAutoUpdatesToSettings(): void {
-  const globalConfig = getGlobalConfig()
-
-  // Only migrate if autoUpdates was explicitly set to false by user preference
-  // (not automatically for native protection)
-  if (
-    globalConfig.autoUpdates !== false ||
-    globalConfig.autoUpdatesProtectedForNative === true
-  ) {
-    return
-  }
-
-  try {
-    const userSettings = getSettingsForSource('userSettings') || {}
-
-    // Always set DISABLE_AUTOUPDATER to preserve user intent
-    // We need to overwrite even if it exists, to ensure the migration is complete
-    updateSettingsForSource('userSettings', {
-      ...userSettings,
-      env: {
-        ...userSettings.env,
-        DISABLE_AUTOUPDATER: '1',
-      },
-    })
-
-    logEvent('tengu_migrate_autoupdates_to_settings', {
-      was_user_preference: true,
-      already_had_env_var: !!userSettings.env?.DISABLE_AUTOUPDATER,
-    })
-
-    // explicitly set, so this takes effect immediately
-    process.env.DISABLE_AUTOUPDATER = '1'
-
-    // Remove autoUpdates from global config after successful migration
-    saveGlobalConfig(current => {
-      const {
-        autoUpdates: _,
-        autoUpdatesProtectedForNative: __,
-        ...updatedConfig
-      } = current
-      return updatedConfig
-    })
-  } catch (error) {
-    logError(new Error(`Failed to migrate auto-updates: ${error}`))
-    logEvent('tengu_migrate_autoupdates_error', {
-      has_error: true,
-    })
-  }
-}