Problem

When using Docxodus in OpenContracts' DocxAnnotator component, any annotation creation/deletion or label filter toggle triggers a full WASM re-conversion of the entire document via convertDocxToHtmlWithExternalAnnotations(). For large legal documents, this causes a noticeable delay on every interaction.

The current useEffect depends on [wasmReady, docxBytes, docText, annotations, visibleLabels, showStructuralAnnotations], meaning any change to annotations or visible labels re-runs the full conversion pipeline.

Desired Behavior

An API that allows updating annotation overlays incrementally (e.g., adding/removing individual annotation spans in the DOM) without re-converting the entire DOCX document from bytes. This would enable:

• Instant annotation creation feedback
• Fast label filter toggling
• Smooth annotation selection highlighting

Possible Approaches

1. Separate conversion and projection: A two-step API where convertDocxToHtml(bytes) produces the base HTML once, and projectAnnotations(html, annotationSet) can be called repeatedly on the same base HTML.
2. DOM-level annotation API: Return a handle/context from the initial conversion that supports addAnnotation() / removeAnnotation() operations directly on the rendered DOM.
3. CSS-only annotation visibility: Use CSS classes for annotation visibility toggling rather than re-rendering (for label filter changes specifically).

Context

Found during code review of OpenContracts PR #1102 which adds first-class DOCX support.