[DRAFT] feat(gcp-sphinx-docfx-yaml): introduce performance optimizations

[daniel-sanche]

The dofx test is our slowest test, taking > 70 minutes for a single package (compute).

This PR attempts to speed up the task by adding optimizations to the gcp-sphinx-docfx-yaml package:

• 2bb74d8: sort known ids once, instead of inside a loop
• 7a1c741: immediately skip over words without "." characters, since they can't be uuids
• c54391e: use custom no-op StandaloneHTMLBuilder class, to avoid doing rendering work for unused html files
• 7b9ab23: use in-process markdown builder, instead of spanning new process and starting from scratch
• 8dedfb7: cache default settings, instead of re-constructing on each node visit

[gemini-code-assist]

Code Review

This pull request optimizes cross-reference conversion by skipping plain words that do not contain dots and hoisting the sorting of known_uids out of a loop. However, the changes introduce a critical NameError because hard_coded_references is referenced in find_uid_to_convert where it is not in scope. The review feedback suggests reverting this reference and instead combining the collections as immutable tuples within convert_cross_references to safely avoid shared state mutation.