style(docs): standardize heading formats and numbering

- Enforce Level 1-3 structural numbering based on SUMMARY.md hierarchy
- Remove structural numbering from Level 4+ headings
- Eliminate single child headings by converting to bold text
- Auto-inject summary text for headings with multiple children missing intro text
- Exclude Appendix chapters from structural numbering
- Avoid modifying code block contents
- Add script to detect non-standard English usage in headers

17_security/kernel_capability.md

@@ -1,4 +1,4 @@
-## 内核能力机制
+## 17.4 内核能力机制
 
 Docker 利用 Linux 的能力机制 (Capabilities) 来限制容器的权限，从而提高系统的安全性。