Summary

• use a known GS25 stock item code for nearby-store fallback so store lookup still works when GS25 totalSearch is rate-limited
• send LotteMart store keywords directly to the upstream store-search endpoint before falling back to broad area scans
• cover the LotteMart upstream keyword parameter and updated GS25 fallback behavior

Verification

• npx vitest run tests/services/gs25/tools/findNearbyStores.test.ts tests/services/lottemart/tools/findNearbyStores.test.ts tests/api/gs25-handlers.test.ts tests/api/lottemart-handlers.test.ts --testTimeout=30000
• npx vitest run tests/app/app-api-lottemart.test.ts --testTimeout=60000
• npm run lint
• npm run typecheck
• npm run build

Refs #45, #46