Dead component image-upload-area.tsx + stale provenance comment referencing it

Audit P3 finding on MARS-647 (e054570): src/components/form/image-upload-area.tsx is exported from form/index.ts with ZERO live consumers, and edit-form.tsx's provenance comment cites it as the reference impl it was copied from — true as a pattern, false as live code. Delete the dead component and correct the now-inaccurate provenance comment together; don't do one without the other.