Apply typedoc-github-theme typography fixes locally via customCss

Backport the `.tsd-typography` CSS fixes from upstream PR
JulianWowra/typedoc-github-theme#7 so document pages render with
GitHub-accurate heading spacing, list bullets, line-height, and code
block overflow. The override file and `customCss` config can be removed
once the PR is merged and the dependency is updated.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

typedoc.config.mjs

@@ -46,6 +46,9 @@ const config = {
     "./scripts/typedoc-plugin-fix-mermaid-entities.mjs",
     "@boneskull/typedoc-plugin-mermaid",
   ],
+  // Remove once typedoc-github-theme merges upstream fix:
+  // https://github.com/JulianWowra/typedoc-github-theme/pull/7
+  customCss: "./scripts/typedoc-github-theme-fixes.css",
   ignoredHighlightLanguages: ["mermaid"],
 };