feat(status): add --porcelain flag for machine-readable output

[vvishuluck]

此 PR 完成了 r2cn 测试任务#1395，为 status 命令添加 --porcelain 参数，提供机器可读的输出格式。

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Project	Deployment	Preview	Comments	Updated (UTC)
mega	Ready	Preview	Comment	Sep 3, 2025 0:44am

[Copilot]

Pull Request Overview

This PR adds a --porcelain flag to the status command for machine-readable output, implementing task #1395. The porcelain format provides a standardized, parseable output format similar to Git's status command.

• Adds StatusArgs struct with porcelain flag to control output format
• Implements output_porcelain function for machine-readable status output
• Updates command integration to use the new argument structure

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 3 comments.

File	Description
libra/src/command/status.rs	Adds StatusArgs struct, porcelain output function, and refactors execute function to support both human and machine-readable formats
libra/src/cli.rs	Updates CLI to accept StatusArgs instead of no arguments for status command
libra/src/command/switch.rs	Updates status function calls to use new StatusArgs::default()
libra/tests/command/status_test.rs	Adds comprehensive tests for porcelain output format and integration testing

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[genedna]

@vvishuluck , 请在 https://github.com/web3infra-foundation/mega/tree/main/aria/contents/docs/libra/command/status 这些命令的页面更新说明