C2: option→subject binding UX (auto-suggest / name-match / manual claim)

When a user creates or edits an option, auto-suggest matching subjects by name similarity and let them bind option.subject_id. Three entry points: (1) auto-suggest on option create — if name matches a known subject, show "Link to [Subject]?" prompt; (2) name-match scan — a background job or on-save trigger that finds unlinked options whose name matches a subject; (3) manual claim — on /s/[slug] an authed user can claim "my option [X] is this product". Requires: fuzzy name match RPC, a UI affordance in the option form or a dedicated binding flow, RLS rules on subject_id writes. Deferred from public-surface build-out (2026-06-14, commit 061239c0).