Adds a focused figure and table review lane for the collaborative research editor.

What changed:

• Adds collab-figure-table-review-lane/ as a small dependency-free module.
• Checks whether figure/table assets are safe to freeze before submission review.
• Blocks sections with missing assets, active edits, open comments, or stale notebook outputs.
• Reports weak captions and missing cross-references as warnings instead of hard failures.
• Includes a README, test script, and demo script.

Validation:

• node collab-figure-table-review-lane/test.js
• node collab-figure-table-review-lane/demo.js

/claim #12