feat(docx-markdoc): preserve existing revisions during annotation projection

[stevenobiajulu]

Summary

docx-markdoc cannot compile annotation presentation projections when the source DOCX already contains tracked revisions. Compilation fails with EXISTING_REVISIONS_UNSUPPORTED, even when the requested change is limited to editing or re-presenting canonical comments/footnotes.

This prevents brownfield annotation workflows from operating directly on negotiated documents that already contain redlines. Accepting the revisions on a derivative allows annotation compilation to proceed, but destructively changes the review state and should not be required.

Privacy-safe reproduction

Use a synthetic DOCX built with the shared fixture infrastructure:

1. Create a document with at least one existing w:ins or w:del revision.
2. Add a supported ranged or point comment and/or a supported point footnote.
3. Import it with importDocxToMarkdoc.
4. Edit an annotation body or set an explicit presentation="comment", presentation="footnote", or presentation="preserve" choice.
5. Call compileMarkdoc using the anchored source.

Actual result: compilation fails with EXISTING_REVISIONS_UNSUPPORTED before annotation projection can complete.

Control: accept the pre-existing revisions on a disposable derivative, repeat the import/edit/compile workflow, and annotation preservation/projection succeeds.

Expected behavior

Annotation-only compilation should preserve pre-existing tracked revisions exactly while applying annotation body edits and presentation projection. It must not accept, reject, flatten, duplicate, or re-author existing revisions.

If exact preservation cannot be proven for a particular topology, compilation should fail atomically with structured, annotation-specific and revision-specific diagnostics.

Acceptance criteria

• A source containing supported pre-existing tracked revisions can import and compile supported annotations without accepting or rejecting those revisions.
• Existing revision XML, authorship, dates, IDs, accept/reject semantics, and story placement remain intact.
• Comment and footnote bodies can be edited and reopened successfully.
• preserve, comment, and footnote projections work from the same canonical annotation IR.
• Point and range geometry follows the canonical paragraph-index/visible-coordinate SSOT.
• Verification proves both annotation dispositions and preservation of pre-existing revisions.
• Unsupported combinations fail atomically with structured diagnostics.
• Tests use shared synthetic DOCX fixtures and include accept/reject round-trip assertions.

Regression coverage

• existing insertion plus ranged comment body edit;
• existing deletion plus point comment body edit;
• existing revisions plus point footnote body edit;
• comment-to-footnote and footnote-to-point-comment projections;
• reply topology alongside existing revisions;
• revisions in supported ancillary stories, where applicable;
• ambiguous or unsupported revision/annotation topology fails closed.