Update 8 documentation files to reflect new URL scheme:
- Dev: /platforms/{code}/storefront/{store_code}/
- Prod: subdomain.platform.lu/ (root path = storefront)
- Rename DEFAULT_PLATFORM_CODE to MAIN_PLATFORM_CODE
- Replace hardcoded platform_id=1 with dynamic values
- Update route examples, middleware descriptions, code samples
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>