feat(subscriptions): migrate subscription management to merchant level and seed tiers

Move subscription create/edit from store detail (broken endpoint) to merchant
detail page with proper modal UI. Seed 4 subscription tiers (Essential,
Professional, Business, Enterprise) in init_production.py. Also includes
cross-module dependency declarations, store domain platform_id migration,
platform context middleware, CMS route fixes, and migration backups.

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

app/modules/cms/routes/api/store_content_pages.py

@@ -34,6 +34,25 @@ store_content_pages_router = APIRouter(prefix="/content-pages")
 logger = logging.getLogger(__name__)
 
 
+def _resolve_platform_id(db: Session, store_id: int) -> int | None:
+    """Resolve platform_id from store's primary StorePlatform. Returns None if not found."""
+    from app.modules.tenancy.models import StorePlatform
+    primary_sp = (
+        db.query(StorePlatform)
+        .filter(StorePlatform.store_id == store_id, StorePlatform.is_primary.is_(True))
+        .first()
+    )
+    if primary_sp:
+        return primary_sp.platform_id
+    # Fallback: any active store_platform
+    any_sp = (
+        db.query(StorePlatform)
+        .filter(StorePlatform.store_id == store_id, StorePlatform.is_active.is_(True))
+        .first()
+    )
+    return any_sp.platform_id if any_sp else None
+
+
 # ============================================================================
 # STORE CONTENT PAGES
 # ============================================================================
@@ -50,8 +69,9 @@ def list_store_pages(
 
     Returns store-specific overrides + platform defaults (store overrides take precedence).
     """
+    platform_id = _resolve_platform_id(db, current_user.token_store_id)
     pages = content_page_service.list_pages_for_store(
-        db, store_id=current_user.token_store_id, include_unpublished=include_unpublished
+        db, platform_id=platform_id, store_id=current_user.token_store_id, include_unpublished=include_unpublished
     )
 
     return [page.to_dict() for page in pages]
@@ -148,11 +168,10 @@ def get_platform_default(
     Useful for stores to view the original before/after overriding.
     """
     # Get store's platform
-    store = store_service.get_store_by_id_optional(db, current_user.token_store_id)
-    platform_id = 1  # Default to OMS
-
-    if store and store.platforms:
-        platform_id = store.platforms[0].id
+    platform_id = _resolve_platform_id(db, current_user.token_store_id)
+    if platform_id is None:
+        from fastapi import HTTPException
+        raise HTTPException(status_code=400, detail="Store is not subscribed to any platform")
 
     # Get platform default (store_id=None)
     page = content_page_service.get_store_default_page(
@@ -177,8 +196,10 @@ def get_page(
 
     Returns store override if exists, otherwise platform default.
     """
+    platform_id = _resolve_platform_id(db, current_user.token_store_id)
     page = content_page_service.get_page_for_store_or_raise(
         db,
+        platform_id=platform_id,
         slug=slug,
         store_id=current_user.token_store_id,
         include_unpublished=include_unpublished,

app/modules/cms/routes/api/storefront.py

@@ -36,11 +36,13 @@ def get_navigation_pages(request: Request, db: Session = Depends(get_db)):
     Returns store overrides + platform defaults.
     """
     store = getattr(request.state, "store", None)
+    platform = getattr(request.state, "platform", None)
     store_id = store.id if store else None
+    platform_id = platform.id if platform else 1
 
     # Get all published pages for this store
     pages = content_page_service.list_pages_for_store(
-        db, store_id=store_id, include_unpublished=False
+        db, platform_id=platform_id, store_id=store_id, include_unpublished=False
     )
 
     return [
@@ -64,10 +66,13 @@ def get_content_page(slug: str, request: Request, db: Session = Depends(get_db))
     Returns store override if exists, otherwise platform default.
     """
     store = getattr(request.state, "store", None)
+    platform = getattr(request.state, "platform", None)
     store_id = store.id if store else None
+    platform_id = platform.id if platform else 1
 
     page = content_page_service.get_page_for_store_or_raise(
         db,
+        platform_id=platform_id,
         slug=slug,
         store_id=store_id,
         include_unpublished=False,  # Only show published pages