Writing picture enrichment annotations to Markdown file

### Image annotations to MD
Following the [Figure Enrichment tutorial](https://ds4sd.github.io/docling/examples/develop_picture_enrichment/) it is easy to add classification metadata to an image through the `element.annotations.append(data)` function.

However this data is not stored during the export to Markdown format. Would there be a way to write it alongside the image path in the final MD document ? Would be great for our RAG application.

Start with the Figure Enrichment tutorial and the `element.annotations.append(data)` entry point, then trace how Markdown export handles image paths. Confirm how annotations should appear alongside each image path in the final Markdown document, and verify the exported output preserves the enrichment metadata for the RAG use case.

Written by the indexing model from the issue text.