为commit命令实现-s参数的功能

[Flash0615]

此 PR 完成了 r2cn 测试任务 #1207 ，为commit命令实现-s参数。

主要变更：

新增 -s/--signoff 选项，用于在提交信息中添加 Signed-off-by 签名；
签名信息自动读取 Git 配置中的 user.name 和 user.email；
签名将追加至提交消息末尾，并保持 Conventional Commits 规范的合规性；
在 test_parse_args() 中新增了 signoff 相关测试，覆盖以下场景：
-s 和 --signoff 选项的解析；
与 --amend 等其他选项的兼容性；
为 CommitArgs 派生了 Default；
新增对 UserConfig 的导入，用于读取用户信息。

影响范围：
完全向后兼容；
无新增依赖，仅使用现有配置系统。

该功能有助于满足 DCO 要求的项目使用场景。

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Name	Status	Preview	Comments	Updated (UTC)
mega	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Jul 12, 2025 3:23pm

[genedna]

@Flash0615 ，

新加入的参数在很多地方没有初始化，需要修复这个问题。

[Copilot]

Pull Request Overview

Adds a new -s/--signoff flag to the commit command so users can automatically append a "Signed-off-by" line using their Git-configured name and email.

• Introduces a signoff boolean flag in CommitArgs with a default of false.
• Reads user.name and user.email from the existing config to format and append the signoff line.
• Updates tests across commands to supply the new signoff field and adds parsing tests for the new flag.

Reviewed Changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
libra/tests/command/switch_test.rs	Added signoff: false to existing CommitArgs in switch tests
libra/tests/command/commit_test.rs	Added signoff: false and new parsing assertions for -s/--signoff
libra/tests/command/checkout_test.rs	Added signoff: false to checkout command tests
libra/tests/command/branch_test.rs	Added signoff: false to branch command tests
libra/src/command/commit.rs	Imported UserConfig, derived Default, added signoff arg, and built commit_message with optional signoff

Comments suppressed due to low confidence (2)

libra/src/command/commit.rs:64

• The format! macro won’t capture {user_name} and {user_email} without named parameters. Use either positional placeholders (format!("Signed-off-by: {} <{}>", user_name, user_email)) or provide named args (format!("Signed-off-by: {user_name} <{user_email}>", user_name=user_name, user_email=user_email)).

        let signoff_line = format!("Signed-off-by: {user_name} <{user_email}>");

[Copilot]

You compute commit_message with the signoff, but later calls to format_commit_msg(&args.message, ...) still use args.message instead of commit_message. You need to pass commit_message into your commit creation functions so the signoff actually appears in the saved commit object.

[genedna]

@Flash0615 需要在 https://github.com/web3infra-foundation/mega/blob/main/aria/contents/docs/libra/command/commit/index.mdx 这个文件中增加 -s 参数的说明