- New component renders button + consent modal + spinner + attribution
- Best-effort warning shown once per session for stock categories
- Hidden if not premium or category kind != 'priced'
- Consent persisted per-profile in user_preferences.price_fetching_consent
- Manual unit_price input remains active in all paths
- 17 vitest tests (no RTL/jsdom — logged MEDIUM in decisions-log.md)
- Wired into SnapshotLineRow/SnapshotEditor/SnapshotEditPage
- asset_type hardcoded to 'stock' pending category schema extension (MEDIUM)
Closes#158
