feat(test-site): add tricky rendering cases for table, diagrams, plugins

[arshinsikka]

What is the purpose of this pull request?

• [ ] Documentation update
• [ ] Bug fix
• [x] Feature addition or enhancement
• [ ] Code maintenance
• [ ] DevOps
• [x] Improve developer experience
• [ ] Others, please explain:

Overview of changes:

• Adds a new test site under packages/core/test/tricky-site/
• Contains individual .md pages for testing rendering of:
  • <table> elements with/without <tbody>
  • <mermaid> flowchart rendering
  • <puml> plugin rendering (inline, named, and external)
  • Shorthand syntax conversion (<span heading> ➝ <span slot="header" ...>)
  • <tree> plugin rendering directory-like structures
  • Auto-anchor injection into heading elements
• Includes a clean index.md for navigation and a complete _site.json
• Test site is self-contained, buildable, and does not interfere with main docs/tests

Anything you'd like to highlight/discuss:

• Let me know if you'd prefer the site be renamed (e.g. render-corner-cases) or placed under a different path.
• This can be extended in future PRs to include more edge cases.

Testing instructions:

To test the site locally: npx markbind serve packages/core/test/tricky-site Navigate to each page and confirm that the rendering reflects expectations.

Proposed commit message: (wrap lines at 72 characters)

feat(test-site): add tricky rendering cases for table, diagrams, plugins

Adds a reusable test site under packages/core/test/tricky-site to visualize rendering of tricky or previously buggy scenarios. Includes pages for <table>, <mermaid>, <puml>, shorthand syntax, tree plugin, and auto-anchors. Helps contributors manually test and verify rendering behavior when working on plugins or layout.

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Checklist: :ballot_box_with_check:

• [x] Updated the documentation for feature additions and enhancements
• [ ] Added tests for bug fixes or features
• [x] Linked all related issues
• [x] No unrelated changes

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Reviewer checklist:

Indicate the [SEMVER](https://semver.org/) impact of the PR:

• [ ] Major (when you make incompatible API changes)
• [x] Minor (when you add functionality in a backward compatible manner)
• [ ] Patch (when you make backward compatible bug fixes)

At the end of the review, please label the PR with the appropriate label: r.Major, r.Minor, r.Patch.

Breaking change release note preparation (if applicable): Not applicable

[arshinsikka]

Update • Moved the test site to packages/cli/test/functional/tricky-site and registered it in testSites. • Converted it into a valid MarkBind site (site.json) with plugins: anchors, mermaid, plantuml, tree; listed all pages. • Added the missing activity.puml referenced by plantuml-diagrams.md. • Removed the earlier folder under packages/core/test/unit. • Added one-line notes clarifying intentional edge cases (headers inside

, duplicate tree entries). Happy to split any parts into unit tests or rename the site if you prefer.

[gerteck]

Hi @arshinsikka thanks for continuing the dev effort! We appreciate new devs working on this project! However, I couldn't see the changes you mentioned reflected in the PR