feat: add import error tracking and translation tabs

Import Error Tracking:
- Add MarketplaceImportError model to store detailed error information
- Store row number, identifier, error type, message, and row data for each error
- Add API endpoint GET /admin/marketplace-import-jobs/{job_id}/errors
- Add UI to view and browse import errors in job details modal
- Support pagination and error type filtering

Translation Tabs:
- Replace flat translation list with tabbed interface on product detail page
- Add language tabs with full language names
- Add copy-to-clipboard functionality for translation content
- Improved UX with better visual separation of translations

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

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

models/database/__init__.py

@@ -20,7 +20,7 @@ from .company import Company
 from .content_page import ContentPage
 from .customer import Customer, CustomerAddress
 from .inventory import Inventory
-from .marketplace_import_job import MarketplaceImportJob
+from .marketplace_import_job import MarketplaceImportError, MarketplaceImportJob
 from .marketplace_product import (
     DigitalDeliveryMethod,
     MarketplaceProduct,
@@ -83,6 +83,7 @@ __all__ = [
     "ProductTranslation",
     # Import
     "MarketplaceImportJob",
+    "MarketplaceImportError",
     # Inventory
     "Inventory",
     # Orders