docs: Mermaid diagrams not rendering in docs site

[KristijanArmeni]

Describe the Feature Request

The Mermaid diagram in our documentation is not rendering on the built website. Zensical has built-in Mermaid support, but it requires a custom_fences configuration under pymdownx.superfences in zensical.toml that is currently missing. Currently we only have one diagram, but good to enable this for future.

See: Zensical Diagrams docs

Relevant files with flowcharts

• docs/guides/design-philosophy/architecture.md (line 26) — Architecture flowchart

Suggested way to address this

Add to zensical.toml:

[project.markdown_extensions.pymdownx.superfences]
custom_fences = [
  { name = "mermaid", class = "mermaid", format = "pymdownx.superfences.fence_code_format" },
]

Testing the fix

Prerequisites: Ensure the docs dependency group is installed in your virtual environment (uv sync --group docs).

1. Build the docs locally: zensical build --clean
2. Serve the docs locally and check that the diagram renders: zensical serve
3. Verify the flowchart at /guides/design-philosophy/architecture/ displays correctly

• Yes
• No