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>
- Add API-002 architecture rule preventing Pydantic imports in API endpoints
- Move inline Pydantic models from vendor_products.py to models/schema/vendor_product.py
- Update vendor_products.py to import schemas from proper location
🤖 Generated with [Claude Code](https://claude.com/claude-code)
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
