fix(docs): improve mkdocs admonition compatibility and robustness

[boboqun]

• normalize admonition types to lowercase (e.g., !!! Note -> ::: note) to match VitePress custom container expectations.
• automatically strip dangling code fences from admonition content to prevent rendering errors caused by malformed markdown (e.g., in docs/coil/compose.md).

fix(docs): enhance mkdocs admonition support for unicode and stability

• Relax regex to \S+ to support non-ASCII admonition types (e.g., !!! 注意).
• Add specific mapping for !!! 注意 to render as ::: note 注意.
• Normalize standard admonition types to lowercase (e.g., !!! Note -> ::: note).
• Automatically strip dangling code fences from admonition content to fix rendering issues in files like docs/coil/compose.md.

[boboqun]

feat: improve MkDocs tabs support in VitePress

• Refactor markdown-it-mk-code-tabs plugin to generate direct <tabs> and <tab> HTML tags instead of ::: tabs containers, aligning with the manual syntax used in other documentation files.
• Fix nested tabs support by flattening indentation of generated HTML tags, preventing markdown-it from parsing them as code blocks.
• Fix fenced code block rendering (e.g., bash) inside tabs by correctly calculating and applying output indentation relative to the parent container.
• Fix parsing of subsequent markdown blocks (e.g., !!! note) by ensuring a blank line is inserted after closing a </tabs> group.
• Enhance Tabs.vue component robustness:
  • Update child filtering logic to explicitly exclude Text, Comment, and Fragment nodes, ensuring all valid tab components are rendered.
  • Add safe navigation for tab titles to prevent runtime errors.