hotfix: Implement Task 7.3 of the marketplace epic — expose averageRa……ting and reviewCount on product responses so the catalog can render star ratings — using a denormalized-counter design (Decision A1) that was already fixed in the phase-7 plan.

[edsonwade]

#Purpose
Implement Task 7.3 of the marketplace epic — expose averageRating and reviewCount on product responses so the catalog can render star ratings — using a denormalized-counter design (Decision A1) that was already fixed in the phase-7 plan.

Current state
Code changes are written and compile clean (mvn test-compile -pl product-service → BUILD SUCCESS), but no tests have been executed and no Docker/Flyway rebuild has happened yet.

-Touched/added:

• V14__add_rating_counters_to_product.sql — new columns + backfill
• Product.java, ProductResponse.java, ProductMapper.java — carry the two new fields through all construction sites (5 constructors, 4 mapper sites)
• ProductRepository.java — native row-locking recomputeRatingCounters update
• ProductCacheKeys.java (new) — single source of truth for cache key names, since tenant fallback logic made ad-hoc key construction unsafe
• ReviewService.java — recomputes counters and evicts only the product-detail cache (list cache intentionally untouched, per A1's no-evict policy)
• Test layers written but not run: ReviewServiceTest (+5 cases), ProductMapperTest, ProductControllerTest, CatalogRatingIntegrationTest (new), ReviewConcurrencyIntegrationTest (new), catalog_rating.feature + CatalogRatingSteps.java (new)
• Plan file correctly relocated to .claude/plans/2026-07-19-f7-task-7.3-catalog-rating-counters.md after an earlier misstep of creating it outside the project
  Two known traps already fixed in code: @Builder.Default dropping initializers in hand-written constructors (would NPE against a NOT NULL column), and the tenant-fallback cache-key mismatch that would have made evictions silently no-op.

#Purpose
Implement Task 7.3 of the marketplace epic — expose averageRating and reviewCount on product responses so the catalog can render star ratings — using a denormalized-counter design (Decision A1) that was already fixed in the phase-7 plan.

Current state
Code changes are written and compile clean (mvn test-compile -pl product-service → BUILD SUCCESS), but no tests have been executed and no Docker/Flyway rebuild has happened yet.

-Touched/added:

• V14__add_rating_counters_to_product.sql — new columns + backfill
• Product.java, ProductResponse.java, ProductMapper.java — carry the two new fields through all construction sites (5 constructors, 4 mapper sites)
• ProductRepository.java — native row-locking recomputeRatingCounters update
• ProductCacheKeys.java (new) — single source of truth for cache key names, since tenant fallback logic made ad-hoc key construction unsafe
• ReviewService.java — recomputes counters and evicts only the product-detail cache (list cache intentionally untouched, per A1's no-evict policy)
• Test layers written but not run: ReviewServiceTest (+5 cases), ProductMapperTest, ProductControllerTest, CatalogRatingIntegrationTest (new), ReviewConcurrencyIntegrationTest (new), catalog_rating.feature + CatalogRatingSteps.java (new)
• Plan file correctly relocated to .claude/plans/2026-07-19-f7-task-7.3-catalog-rating-counters.md after an earlier misstep of creating it outside the project
  Two known traps already fixed in code: @Builder.Default dropping initializers in hand-written constructors (would NPE against a NOT NULL column), and the tenant-fallback cache-key mismatch that would have made evictions silently no-op.