能力已证实，产品化仍差一步。

Skill 不自己画三选一，也不退化成文本列表。它只定义问题与选项；如果当前任务没有工具， 就明确返回不可用。

Call `request_user_input` once:

- Header: `润色方向`
- Question: `请选择这次短文润色的方向。`
- Options:
  1. `自然流畅 (Recommended)`
  2. `生动有画面`
  3. `正式简洁`

If `request_user_input` is unavailable,
report `PICKER_NOT_INSTALLED` exactly.

安装器先核对 Skill 包的 SHA-256，避免把未知内容直接装进用户目录；校验通过后才复制并运行开关脚本。

$actualSha256 = (Get-FileHash $archivePath -Algorithm SHA256).
    Hash.ToLowerInvariant()
if ($actualSha256 -ne $expectedSha256) {
    throw "Package checksum mismatch"
}

Copy-Item -LiteralPath $sourceSkill `
    -Destination $installedSkill -Recurse
$enableScript = Join-Path $installedSkill `
    "scripts\enable-native-picker.ps1"
$featureResult = & powershell.exe -NoProfile `
    -ExecutionPolicy Bypass -File $enableScript |
    ConvertFrom-Json

脚本只修改 [features] 下的目标键：存在就替换，不存在就补入；写入前保留备份，写入后再读回验证。

$feature = "default_mode_request_user_input"
$configPath = Join-Path $env:USERPROFILE `
    ".codex\config.toml"

if (-not (Test-Path -LiteralPath $backupPath)) {
    [IO.File]::WriteAllBytes(
        $backupPath,
        [IO.File]::ReadAllBytes($configPath)
    )
}

$newBody =
    "default_mode_request_user_input = true" +
    $newline + $body

[IO.File]::WriteAllText(
    $configPath, $text, $utf8NoBom
)

if (-not $afterEnabled) {
    throw "Failed to enable $feature"
}