[docs][utest]:Add standardized utest documentation to atomic_tc and mtsafe_kprint_tc

[h0bbl3s]

Relates to #10895

拉取/合并请求描述：(PR description)

Added standardized Utest documentation to the Kernel Core Atomic Operations Test atomic_tc
Added standardized Utest documentation to the Kernel Core MT-Safe Kprint Test mtsafe_kprint_tc

为什么提交这份PR (why to submit this PR)

As stated in the linked task, documentation is missing from some utest source files.
I've been going through the source code during projects recently, and would like to contribute. This seems like a good place to start.

你的解决方案是什么 (what is your solution)

Do a detailed read-through of source and perform trial runs of tests,
then write documentation

当前拉取/合并请求的状态 Intent for your PR

必须选择一项 Choose one (Mandatory):

• 本拉取/合并请求是一个草稿版本 This PR is for a code-review and is intended to get feedback
• 本拉取/合并请求是一个成熟版本 This PR is mature, and ready to be integrated into the repo

代码质量 Code Quality：

我在这个拉取/合并请求中已经考虑了 As part of this pull request, I've considered the following:

• 已经仔细查看过代码改动的对比 Already check the difference between PR and old code
• 代码风格正确，包括缩进空格，命名及其他风格 Style guide is adhered to, including spacing, naming and other styles
• 没有垃圾代码，代码尽量精简，不包含#if 0代码，不包含已经被注释了的代码 All redundant code is removed and cleaned up
• 所有变更均有原因及合理的，并且不会影响到其他软件组件代码或BSP All modifications are justified and not affect other components or BSP
• 对难懂代码均提供对应的注释 I've commented appropriately where code is tricky
• 代码是高质量的 Code in this PR is of high quality
• 已经使用formatting 等源码格式化工具确保格式符合RT-Thread代码规范 This PR complies with RT-Thread code specification
• 如果是新增bsp, 已经添加ci检查到.github/ALL_BSP_COMPILE.json 详细请参考链接BSP自查

[github-actions]

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为确保代码符合 RT-Thread 的编码规范，请在你的仓库中执行以下步骤运行代码格式化工作流（如果格式化CI运行失败）。
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Once completed, commits will be pushed to the dev_1 branch automatically, and the related Pull Request will be updated.

如有问题欢迎联系我们，再次感谢您的贡献！💐
If you have any questions, feel free to reach out. Thanks again for your contribution!

[github-actions]

📌 Code Review Assignment

🏷️ Tag: kernel

Reviewers: GorrayLi ReviewSun hamburger-os lianux-mm wdfk-prog xu18838022837

Changed Files (Click to expand)

• src/utest/atomic_tc.c
• src/utest/mtsafe_kprint_tc.c

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📊 Current Review Status (Last Updated: 2025-11-18 10:45 CST)

• ⌛ GorrayLi Pending Review
• ⌛ ReviewSun Pending Review
• ⌛ hamburger-os Pending Review
• ⌛ lianux-mm Pending Review
• ⌛ wdfk-prog Pending Review
• ⌛ xu18838022837 Pending Review

---

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   Comment LGTM/lgtm after confirming approval

3. PR合并前需至少一位维护者确认
   PR must be confirmed by at least one maintainer before merging

ℹ️ 刷新CI状态操作需要具备仓库写入权限。
ℹ️ Refresh CI status operation requires repository Write permission.

[Copilot]

Pull Request Overview

This PR adds standardized documentation blocks to two kernel core utest files (atomic_tc.c and mtsafe_kprint_tc.c), addressing the documentation gap identified in issue #10895. The documentation follows a consistent template structure with test objectives, scenarios, verification metrics, dependencies, and expected results.

Key Changes:

• Added comprehensive documentation blocks describing test purpose, scenarios, and expected behavior
• Updated copyright year from 2021/2023 to 2025 in both files
• Added change log entries for the documentation additions

Reviewed Changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 6 comments.

File	Description
src/utest/atomic_tc.c	Added standardized documentation block describing atomic operations tests including functional API tests and multi-threaded stress tests
src/utest/mtsafe_kprint_tc.c	Added standardized documentation block describing the MT-safe kprintf stress test with 16 concurrent threads

[h0bbl3s]

Fixing some formatting

[h0bbl3s]

Update copyright dates