fix(scripts): fix model registration and missing platform_id in init scripts

All init scripts (init_log_settings, create_default_content_pages,
create_platform_pages, seed_email_templates) failed because they didn't
register all SQLAlchemy model classes, causing mapper resolution errors
for cross-module relationships (Platform→ContentPage, Platform→SubscriptionTier).

Fixes:
- Add full model registration loop to all 5 init scripts
- Add platform_id (OMS) to content page creation (NOT NULL constraint)
- Add missing db.commit() to create_platform_pages.py (pages were never persisted)
- Add cms.models to init_production.py registration list

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

scripts/init_production.py

@@ -53,6 +53,7 @@ for _mod in [
     "app.modules.customers.models",
     "app.modules.orders.models",
     "app.modules.marketplace.models",
+    "app.modules.cms.models",
 ]:
     try:
         __import__(_mod)