Sprint 2 high-priority cleanup: layout preference read/write called raw
localStorage from a component, violating the no-raw-localStorage rule.
Now uses the shared core/storage/LocalStorageService (same as
cart/language/location services).
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Unify product details modules behind config-driven contracts so teams can
extend UX without changing runtime architecture or bootstrap flow.
Keep backward compatibility with existing product payloads by treating new
media/specification/variant/related structures as optional extensions.
Improve conversion and content discoverability with reusable actions,
typed media rendering, grouped specifications, dynamic variants, and
multi-collection related products.
