refactor: migrate products and vendor_products to module auto-discovery

- Move admin/products.py to marketplace module as admin_products.py
  (marketplace product catalog browsing)
- Move admin/vendor_products.py to catalog module as admin.py
  (vendor catalog management)
- Move vendor/products.py to catalog module as vendor.py
  (vendor's own product catalog)
- Update marketplace admin router to include products routes
- Update catalog module routes/api/__init__.py with lazy imports
- Remove legacy imports from admin and vendor API init files

All product routes now auto-discovered via module system.

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

app/modules/catalog/routes/api/admin.py

@@ -0,0 +1,160 @@
+# app/modules/catalog/routes/api/admin.py
+"""
+Admin vendor product catalog endpoints.
+
+Provides management of vendor-specific product catalogs:
+- Browse products in vendor catalogs
+- View product details with override info
+- Create/update/remove products from catalog
+
+All routes require module access control for the 'catalog' module.
+"""
+
+import logging
+
+from fastapi import APIRouter, Depends, Query
+from sqlalchemy.orm import Session
+
+from app.api.deps import get_current_admin_api, require_module_access
+from app.core.database import get_db
+from app.services.subscription_service import subscription_service
+from app.services.vendor_product_service import vendor_product_service
+from models.schema.auth import UserContext
+from app.modules.catalog.schemas import (
+    CatalogVendor,
+    CatalogVendorsResponse,
+    RemoveProductResponse,
+    VendorProductCreate,
+    VendorProductCreateResponse,
+    VendorProductDetail,
+    VendorProductListItem,
+    VendorProductListResponse,
+    VendorProductStats,
+    VendorProductUpdate,
+)
+
+admin_router = APIRouter(
+    prefix="/vendor-products",
+    dependencies=[Depends(require_module_access("catalog"))],
+)
+logger = logging.getLogger(__name__)
+
+
+# ============================================================================
+# Endpoints
+# ============================================================================
+
+
+@admin_router.get("", response_model=VendorProductListResponse)
+def get_vendor_products(
+    skip: int = Query(0, ge=0),
+    limit: int = Query(50, ge=1, le=500),
+    search: str | None = Query(None, description="Search by title or SKU"),
+    vendor_id: int | None = Query(None, description="Filter by vendor"),
+    is_active: bool | None = Query(None, description="Filter by active status"),
+    is_featured: bool | None = Query(None, description="Filter by featured status"),
+    language: str = Query("en", description="Language for title lookup"),
+    db: Session = Depends(get_db),
+    current_admin: UserContext = Depends(get_current_admin_api),
+):
+    """
+    Get all products in vendor catalogs with filtering.
+
+    This endpoint allows admins to browse products that have been
+    copied to vendor catalogs from the marketplace repository.
+    """
+    products, total = vendor_product_service.get_products(
+        db=db,
+        skip=skip,
+        limit=limit,
+        search=search,
+        vendor_id=vendor_id,
+        is_active=is_active,
+        is_featured=is_featured,
+        language=language,
+    )
+
+    return VendorProductListResponse(
+        products=[VendorProductListItem(**p) for p in products],
+        total=total,
+        skip=skip,
+        limit=limit,
+    )
+
+
+@admin_router.get("/stats", response_model=VendorProductStats)
+def get_vendor_product_stats(
+    vendor_id: int | None = Query(None, description="Filter stats by vendor ID"),
+    db: Session = Depends(get_db),
+    current_admin: UserContext = Depends(get_current_admin_api),
+):
+    """Get vendor product statistics for admin dashboard."""
+    stats = vendor_product_service.get_product_stats(db, vendor_id=vendor_id)
+    return VendorProductStats(**stats)
+
+
+@admin_router.get("/vendors", response_model=CatalogVendorsResponse)
+def get_catalog_vendors(
+    db: Session = Depends(get_db),
+    current_admin: UserContext = Depends(get_current_admin_api),
+):
+    """Get list of vendors with products in their catalogs."""
+    vendors = vendor_product_service.get_catalog_vendors(db)
+    return CatalogVendorsResponse(vendors=[CatalogVendor(**v) for v in vendors])
+
+
+@admin_router.get("/{product_id}", response_model=VendorProductDetail)
+def get_vendor_product_detail(
+    product_id: int,
+    db: Session = Depends(get_db),
+    current_admin: UserContext = Depends(get_current_admin_api),
+):
+    """Get detailed vendor product information including override info."""
+    product = vendor_product_service.get_product_detail(db, product_id)
+    return VendorProductDetail(**product)
+
+
+@admin_router.post("", response_model=VendorProductCreateResponse)
+def create_vendor_product(
+    data: VendorProductCreate,
+    db: Session = Depends(get_db),
+    current_admin: UserContext = Depends(get_current_admin_api),
+):
+    """Create a new vendor product."""
+    # Check product limit before creating
+    subscription_service.check_product_limit(db, data.vendor_id)
+
+    product = vendor_product_service.create_product(db, data.model_dump())
+    db.commit()
+    return VendorProductCreateResponse(
+        id=product.id, message="Product created successfully"
+    )
+
+
+@admin_router.patch("/{product_id}", response_model=VendorProductDetail)
+def update_vendor_product(
+    product_id: int,
+    data: VendorProductUpdate,
+    db: Session = Depends(get_db),
+    current_admin: UserContext = Depends(get_current_admin_api),
+):
+    """Update a vendor product."""
+    # Only include fields that were explicitly set
+    update_data = data.model_dump(exclude_unset=True)
+    vendor_product_service.update_product(db, product_id, update_data)
+    db.commit()
+    # Return the updated product detail
+    product = vendor_product_service.get_product_detail(db, product_id)
+    return VendorProductDetail(**product)
+
+
+@admin_router.delete("/{product_id}", response_model=RemoveProductResponse)
+def remove_vendor_product(
+    product_id: int,
+    db: Session = Depends(get_db),
+    current_admin: UserContext = Depends(get_current_admin_api),
+):
+    """Remove a product from vendor catalog."""
+    result = vendor_product_service.remove_product(db, product_id)
+    db.commit()
+    return RemoveProductResponse(**result)