docs: use MathJax SVG renderer for HTML equations

[dhutererprats]

• Tickets addressed: N/A (documentation rendering quality fix)
• Review: By commit
• Merge strategy: Merge (no squash)

Description

This PR addresses a global HTML documentation rendering issue where some math expressions show vertically misaligned characters in certain local browser/font environments.

The issue is not module-specific. It affects equation rendering across Basilisk docs because it originates in the shared Sphinx/MathJax configuration.

What changed

• Updated:

  • docs/source/conf.py

• Switched MathJax output mode from CHTML to SVG:

  • mathjax_path = "https://cdn.jsdelivr.net/npm/mathjax@3/es5/tex-svg.js"
  • mathjax3_config = {"svg": {"fontCache": "global"}}

No simulation models, algorithms, message interfaces, or unit tests are modified.

RFT (Rendering Fault Type)

RFT-Category: Documentation rendering / browser typography mismatch

Observed failure mode:

• In some environments, multi-character math tokens can appear with alternating vertical character offsets (a “staggered” or “wavy” look).
• Example pattern: terms such as B_{overlap} may render with inconsistent baseline alignment between letters in the subscripted token.

Why this happens:

• MathJax CHTML rendering depends on local font metrics and browser fallback behavior.
• Metric mismatch in fallback paths can produce visible baseline artifacts.

Why SVG fixes it:

• MathJax SVG output uses deterministic vector glyph layout.
• This removes dependence on local font metric fallback for equation composition and eliminates the observed vertical offset artifacts.

Scope and Impact

Affected scope

• HTML equation rendering across Basilisk documentation pages.

Not affected

• Runtime simulation behavior
• C++ / Python implementation logic
• Message payload definitions
• Test behavior/results

Verification

Checks performed:

• Full docs build succeeds (with the same baseline warning profile for optional components/dependencies).
• Generated HTML now references MathJax SVG renderer (tex-svg.js).
• Equations render consistently without the observed vertical character offset artifact.