Improve kernel cleanup UX, menu layout, and XanMod repo handlin

[Aethersailor]

• 删除保留内核
  增加自动检测 /boot 内核列表并标记最新版本的功能，用户直接回车即默认使用最新内核版本号作为保留的关键词。

• 修正“删除保留保留保留内核”提示文案与标点，避免重复字样。
  修复一处文字错误。

• 优化显示效果
  统一脚本内中文提示/注释的中英文间，提高可读性。调整主菜单项左右对齐与间距，适配 CJK 宽度显示。

• XanMod APT 源配置去重
  安装 xanmod 内核时，现在会检测 deb822 支持并自动选择 .sources或.list，同时清理重复文件并提示 sources.list 冲突。
  从而避免在使用 .sources 的系统中，重复添加 .sources/.list 造成 apt 出现警告信息

[Copilot]

Pull request overview

This pull request focuses on improving user experience for kernel cleanup operations, enhancing menu layout for better readability with CJK characters, and implementing smarter XanMod repository management to avoid duplicate source configurations.

Changes:

• Enhanced kernel cleanup UX by automatically detecting /boot kernel versions, marking the latest version, and defaulting to it when user presses Enter
• Improved menu layout with adjusted spacing and alignment for better CJK (Chinese-Japanese-Korean) character display
• Added intelligent XanMod APT repository handling with deb822 (.sources) format support detection, automatic deduplication between .list and .sources files, and conflict warnings for sources.list entries
• Standardized Chinese text formatting throughout the script by adding proper spacing between Chinese and English/numeric characters for improved readability

Comments suppressed due to low confidence (1)

tcpx.sh:1318

• The helper functions gototcp, gototeddysun_bbr, gotodd, and gotoipcheck each execute remote scripts via constructs like bash <(wget -qO- https://github.com/.../raw/master/xxx.sh) and bash <(wget -qO- https://raw.githubusercontent.com/xykt/IPQuality/main/ip.sh) with elevated privileges and no integrity verification. This creates a strong supply-chain attack vector: if any of those remote repositories or the network path is compromised, arbitrary code will be executed on the host when these menu options are used. These installers should not execute mutable remote URLs directly; instead, pin to vetted artifacts and verify their integrity (e.g., via checksums or signatures) before running them, or vendor the scripts locally.

	bash <(wget -qO- https://github.com/ylx2016/Linux-NetSpeed/raw/master/tcp.sh)
}

#切换到秋水逸冰 BBR 安装脚本
gototeddysun_bbr() {
	clear
	bash <(wget -qO- https://github.com/teddysun/across/raw/master/bbr.sh)
}

#切换到一键 DD 安装系统脚本 新手勿入
gotodd() {
	clear
	echo DD 使用 git.beta.gs 的脚本，知悉
	sleep 1.5
	bash <(wget -qO- https://github.com/fcurrk/reinstall/raw/master/NewReinstall.sh)
}

#切换到检查当前 IP 质量/媒体解锁/邮箱通信脚本
gotoipcheck() {
	clear
	sleep 1.5
	bash <(wget -qO- https://raw.githubusercontent.com/xykt/IPQuality/main/ip.sh)

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.