- Create platform_service.py to move DB queries from platforms.py API
- Create platform.py exceptions for PlatformNotFoundException
- Update platforms.py API to use platform_service
- Update vendor/content_pages.py to use vendor_service
- Add get_vendor_by_id_optional method to VendorService
- Fix platforms.js: add centralized logger and init guard
- Fix content-page-edit.html: use modal macro instead of inline modal
All 21 architecture validation errors resolved.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>