Fix archive-providers/mdo-providers reference generator; emit MDX directly

[digitaldiina]

Tracking issue for a new Azure DevOps work item: fix the archive-providers/mdo-providers reference generator's known formatting defects at the source, and have it emit Mintlify MDX directly.

Current output: en/api/archive-providers/reference/ (373 files) and en/api/mdo-providers/reference/ (422 files), both .md, generated: true + envir: onsite, online frontmatter. Known defects were found and categorized while fixing Mintlify build errors on the documentation side — see #122 for the full breakdown — and are currently client-side patched by tools/fix-archive-providers-mdx.ps1 in this repo.

Acceptance criteria

Parallel generation

• A new Mintlify archive-providers/mdo-providers MDX generation process is added.
• The existing DocFX generation for this content continues to run unchanged.
• Existing DocFX output in superoffice-docs is not overwritten, removed, renamed, or redirected.
• The Mintlify generation is sufficiently isolated to be moved into its own pipeline and pull request later.

Files and locations

• Generated archive-providers pages continue to land at en/api/archive-providers/reference/.
• Generated mdo-providers pages continue to land at en/api/mdo-providers/reference/.
• All generated pages use the .mdx extension.
• Generated slugs use one consistent casing convention across both providers (current mdo-providers nav mixes cases).
• config/nav-archive-providers.json / config/nav-mdo-providers.json continue to be generated as flat JSON arrays of page paths, index first, with corrected/consistent casing.

Known generator defects — fixed at the source, not patched after the fact

• The hardcoded stray orphaned </p> after the "See also" line at end-of-file is no longer produced (357 instances, archive-providers).
• The trailing | on the ## Supported Columns table header row is always present (358 instances / 248 files, archive-providers).
• Unbalanced ( in column-description cells is handled wherever it occurs in the string, not just at the edges.

Frontmatter

• Each generated page retains title, description, generated: true, content_type: reference, envir.

Legacy navigation

• The generator does not create or update a legacy toc.yml for this content.
• The generator does not modify docs.json directly — the nav files above are consumed via $ref, same as today.

Validation and testing

• A representative sample of generated pages from both archive-providers and mdo-providers is tested locally in the Mintlify project.
• Testing confirms none of the three known defect patterns above reproduce.
• No MDX parsing errors are produced.

Cleanup tasks

• Once the generator fix lands and is verified, delete tools/fix-archive-providers-mdx.ps1 (including its hardcoded lookup table) from this repo.
• Normalize the already-present mixed-case slugs in config/nav-mdo-providers.json.