add integration tests for product, cart and home pages

37 new LiveView integration tests covering the three previously
untested shop pages. Product detail tests cover variant selection,
price updates and add-to-cart. Cart tests use DB fixtures with
session seeding for hydration. Home tests cover hero, categories,
featured products and navigation links. 612 total tests.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

PROGRESS.md

@@ -209,13 +209,15 @@ All 8 items from the plan done. Key wins: ThemeHook eliminated mount duplication
 See: [docs/plans/dry-refactor.md](docs/plans/dry-refactor.md) for full analysis and plan
 
 ### Shop Page Integration Tests
-**Status:** Follow-up
+**Status:** Complete
 
-Home, product detail, and cart pages have no LiveView integration tests. Collection and content pages are well-covered (16 and 10 tests respectively). Priority order by logic complexity:
+All shop pages now have LiveView integration tests (612 total):
 
-1. **Product detail page** — variant selection, add-to-cart, gallery, breadcrumb
-2. **Cart page** — cart items, quantity changes, order summary, checkout link
-3. **Home page** — hero section, featured products, category nav (mostly presentational)
+- **Product detail page** (15 tests) — rendering, breadcrumbs, variant selection, price updates, add-to-cart, related products, fallback for unknown IDs
+- **Cart page** (10 tests) — empty state, item display with DB fixtures, order summary, increment/decrement, remove, checkout button
+- **Home page** (12 tests) — hero section, category nav, featured products, image+text section, navigation links
+- **Collection page** (16 tests, pre-existing) — category filtering, sorting, URL params
+- **Content pages** (10 tests, pre-existing) — about, delivery, privacy, terms
 
 ### Page Editor
 **Status:** Future (Tier 4)