refactor: product independence - remove inheritance pattern

Change Product/ProductTranslation from "override/inheritance" pattern
(NULL = inherit from marketplace) to "independent copy" pattern
(all fields populated at creation).

Key changes:
- Remove OVERRIDABLE_FIELDS, effective_* properties, reset_* methods
- Rename get_override_info() → get_source_comparison_info()
- Update copy_to_vendor_catalog() to copy ALL fields + translations
- Replace effective_* with direct field access in services
- Remove *_overridden fields from schema, keep *_source for comparison
- Add migration to populate NULL fields from marketplace products

The marketplace_product_id FK is kept for "view original source" feature.
Rollback tag: v1.0.0-pre-product-independence

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

app/services/cart_service.py

@@ -176,8 +176,8 @@ class CartService:
 
         # Get current price in cents (use sale_price if available, otherwise regular price)
         current_price_cents = (
-            product.effective_sale_price_cents
-            or product.effective_price_cents
+            product.sale_price_cents
+            or product.price_cents
             or 0
         )
 

app/services/marketplace_product_service.py

@@ -835,10 +835,18 @@ class MarketplaceProductService:
         """
         Copy marketplace products to a vendor's catalog.
 
+        Creates independent vendor products with ALL fields copied from the
+        marketplace product. Each vendor product is a standalone entity - no
+        field inheritance or fallback logic. The marketplace_product_id FK is
+        kept for "view original source" feature.
+
+        Also copies ALL translations from the marketplace product.
+
         Returns:
             Dict with copied, skipped, failed counts and details
         """
         from models.database.product import Product
+        from models.database.product_translation import ProductTranslation
         from models.database.vendor import Vendor
 
         vendor = db.query(Vendor).filter(Vendor.id == vendor_id).first()
@@ -849,6 +857,7 @@ class MarketplaceProductService:
 
         marketplace_products = (
             db.query(MarketplaceProduct)
+            .options(joinedload(MarketplaceProduct.translations))
             .filter(MarketplaceProduct.id.in_(marketplace_product_ids))
             .all()
         )
@@ -883,19 +892,58 @@ class MarketplaceProductService:
                     )
                     continue
 
+                # Create vendor product with ALL fields copied from marketplace
                 product = Product(
                     vendor_id=vendor_id,
                     marketplace_product_id=mp.id,
+                    # === Vendor settings (defaults) ===
                     is_active=True,
                     is_featured=False,
-                    # Copy GTIN for order matching
+                    # === Product identifiers ===
                     gtin=mp.gtin,
                     gtin_type=mp.gtin_type if hasattr(mp, "gtin_type") else None,
+                    # === Pricing (copy from marketplace) ===
+                    price_cents=mp.price_cents,
+                    sale_price_cents=mp.sale_price_cents,
+                    currency=mp.currency or "EUR",
+                    # === Product info ===
+                    brand=mp.brand,
+                    condition=mp.condition,
+                    availability=mp.availability,
+                    # === Media ===
+                    primary_image_url=mp.image_link,
+                    additional_images=mp.additional_images,
+                    # === Digital product fields ===
+                    download_url=mp.download_url if hasattr(mp, "download_url") else None,
+                    license_type=mp.license_type if hasattr(mp, "license_type") else None,
                 )
 
                 db.add(product)
+                db.flush()  # Get product.id for translations
+
+                # Copy ALL translations from marketplace product
+                translations_copied = 0
+                for mpt in mp.translations:
+                    product_translation = ProductTranslation(
+                        product_id=product.id,
+                        language=mpt.language,
+                        title=mpt.title,
+                        description=mpt.description,
+                        short_description=mpt.short_description,
+                        meta_title=mpt.meta_title,
+                        meta_description=mpt.meta_description,
+                        url_slug=mpt.url_slug,
+                    )
+                    db.add(product_translation)
+                    translations_copied += 1
+
                 copied += 1
-                details.append({"id": mp.id, "status": "copied", "gtin": mp.gtin})
+                details.append({
+                    "id": mp.id,
+                    "status": "copied",
+                    "gtin": mp.gtin,
+                    "translations_copied": translations_copied,
+                })
 
             except Exception as e:
                 logger.error(f"Failed to copy product {mp.id}: {str(e)}")

app/services/order_service.py

@@ -340,8 +340,8 @@ class OrderService:
 
                 # Get price in cents (prefer sale price, then regular price)
                 unit_price_cents = (
-                    product.effective_sale_price_cents
-                    or product.effective_price_cents
+                    product.sale_price_cents
+                    or product.price_cents
                 )
                 if not unit_price_cents:
                     raise ValidationException(f"Product {product.id} has no price")

app/services/vendor_product_service.py

@@ -171,9 +171,9 @@ class VendorProductService:
             raise ProductNotFoundException(product_id)
 
         mp = product.marketplace_product
-        override_info = product.get_override_info()
+        source_comparison_info = product.get_source_comparison_info()
 
-        # Get marketplace product translations
+        # Get marketplace product translations (for "view original source")
         mp_translations = {}
         if mp:
             for t in mp.translations:
@@ -183,7 +183,7 @@ class VendorProductService:
                     "short_description": t.short_description,
                 }
 
-        # Get vendor translations (overrides)
+        # Get vendor translations
         vendor_translations = {}
         for t in product.translations:
             vendor_translations[t.language] = {
@@ -198,8 +198,8 @@ class VendorProductService:
             "vendor_code": product.vendor.vendor_code if product.vendor else None,
             "marketplace_product_id": product.marketplace_product_id,
             "vendor_sku": product.vendor_sku,
-            # Override info
-            **override_info,
+            # Product fields with source comparison info
+            **source_comparison_info,
             # Vendor-specific fields
             "is_featured": product.is_featured,
             "is_active": product.is_active,
@@ -270,13 +270,13 @@ class VendorProductService:
             "marketplace_product_id": product.marketplace_product_id,
             "vendor_sku": product.vendor_sku,
             "title": title,
-            "brand": product.effective_brand,
-            "effective_price": product.effective_price,
-            "effective_currency": product.effective_currency,
+            "brand": product.brand,
+            "price": product.price,
+            "currency": product.currency,
             "is_active": product.is_active,
             "is_featured": product.is_featured,
             "is_digital": product.is_digital,
-            "image_url": product.effective_primary_image_url,
+            "image_url": product.primary_image_url,
             "source_marketplace": mp.marketplace if mp else None,
             "source_vendor": mp.vendor_name if mp else None,
             "created_at": product.created_at.isoformat()