Support for lightweight Linux distributions without apt-get

# Lightweight dotfiles configuration for Alpine Linux

## Points to note in the Alpine environment
- `apt-get` → `apk`
- `rcm` → Manual configuration
- Ubuntu-based tools cannot be used

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# Alpine Linux対応の軽量dotfiles設定

## Alpine環境での注意点
- `apt-get` → `apk`
- `rcm` → 手動設定
- Ubuntuベースのツールは使用不可

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