Wire createPicker into the preview-agent IIFE: enter/exit picker via host messages, bind DOM mousemove/click (capture phase) to picker hover/select, and on click emit a selection event carrying ElementMetadata + annotated screenshot. Route the selection event in previewEvents.ts through buildSelectionComposerText into queueComposerPrefill with the screenshot attachment.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>