fix: correct tojson|safe usage in templates and update validator

- Remove |safe from |tojson in HTML attributes (x-data) - quotes must
  become " for browsers to parse correctly
- Update LANG-002 and LANG-003 architecture rules to document correct
  |tojson usage patterns:
  - HTML attributes: |tojson (no |safe)
  - Script blocks: |tojson|safe
- Fix validator to warn when |tojson|safe is used in x-data (breaks
  HTML attribute parsing)
- Improve code quality across services, APIs, and tests

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

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

tests/unit/utils/test_csv_processor.py

@@ -10,7 +10,6 @@ import requests.exceptions
 
 from app.utils.csv_processor import CSVProcessor
 from models.database.marketplace_product import MarketplaceProduct
-from models.database.marketplace_product_translation import MarketplaceProductTranslation
 
 
 @pytest.mark.unit