Elements detected as interactive via heuristic methods (cursor:pointer
style, interactive class names, event listeners) had empty attributes
because `isInteractiveCandidate()` was used as the gate for attribute
extraction. This function only recognizes standard HTML tags and ARIA
attributes, missing heuristic detections.
After interactivity is confirmed by `isInteractiveElement()`, backfill
attributes for elements that were missed. This ensures
`includeAttributes` (e.g. `['class']`) works correctly for all
interactive elements, not just semantically standard ones.
Closes#124
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>