refactor(arch): move auth schemas to tenancy module and add cross-module service methods

Move all auth schemas (UserContext, UserLogin, LoginResponse, etc.) from
legacy models/schema/auth.py to app/modules/tenancy/schemas/auth.py per
MOD-019. Update 84 import sites across 14 modules. Legacy file now
re-exports for backwards compatibility.

Add missing tenancy service methods for cross-module consumers:
- merchant_service.get_merchant_by_owner_id()
- merchant_service.get_merchant_count_for_owner()
- admin_service.get_user_by_id() (public, was private-only)
- platform_service.get_active_store_count()

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

app/modules/marketplace/routes/api/admin_letzshop.py

@@ -64,7 +64,7 @@ from app.modules.orders.exceptions import OrderHasUnresolvedExceptionsException
 from app.modules.orders.services.order_item_exception_service import (
     order_item_exception_service,
 )
-from models.schema.auth import UserContext
+from app.modules.tenancy.schemas.auth import UserContext
 
 admin_letzshop_router = APIRouter(
     prefix="/letzshop",

app/modules/marketplace/routes/api/admin_marketplace.py

@@ -27,8 +27,8 @@ from app.modules.marketplace.schemas import (
 from app.modules.marketplace.services.marketplace_import_job_service import (
     marketplace_import_job_service,
 )
+from app.modules.tenancy.schemas.auth import UserContext
 from app.modules.tenancy.services.store_service import store_service
-from models.schema.auth import UserContext
 
 admin_marketplace_router = APIRouter(
     prefix="/marketplace-import-jobs",

app/modules/marketplace/routes/api/admin_products.py

@@ -24,7 +24,7 @@ from app.modules.enums import FrontendType
 from app.modules.marketplace.services.marketplace_product_service import (
     marketplace_product_service,
 )
-from models.schema.auth import UserContext
+from app.modules.tenancy.schemas.auth import UserContext
 
 admin_products_router = APIRouter(
     prefix="/products",

app/modules/marketplace/routes/api/store_letzshop.py

@@ -55,7 +55,7 @@ from app.modules.orders.exceptions import OrderHasUnresolvedExceptionsException
 from app.modules.orders.services.order_item_exception_service import (
     order_item_exception_service,
 )
-from models.schema.auth import UserContext
+from app.modules.tenancy.schemas.auth import UserContext
 
 store_letzshop_router = APIRouter(
     prefix="/letzshop",

app/modules/marketplace/routes/api/store_marketplace.py

@@ -23,9 +23,9 @@ from app.modules.marketplace.schemas import (
 from app.modules.marketplace.services.marketplace_import_job_service import (
     marketplace_import_job_service,
 )
+from app.modules.tenancy.schemas.auth import UserContext
 from app.modules.tenancy.services.store_service import store_service
 from middleware.decorators import rate_limit
-from models.schema.auth import UserContext
 
 store_marketplace_router = APIRouter(
     prefix="/marketplace",

app/modules/marketplace/routes/api/store_onboarding.py

@@ -38,7 +38,7 @@ from app.modules.marketplace.schemas import (
     ProductImportConfigResponse,
 )
 from app.modules.marketplace.services.onboarding_service import OnboardingService
-from models.schema.auth import UserContext
+from app.modules.tenancy.schemas.auth import UserContext
 
 store_onboarding_router = APIRouter(
     prefix="/onboarding",

app/modules/marketplace/tests/integration/test_store_page_routes.py

@@ -25,8 +25,8 @@ from app.modules.marketplace.models import OnboardingStatus, StoreOnboarding
 from app.modules.tenancy.models import Merchant, Platform, Store, User
 from app.modules.tenancy.models.platform_module import PlatformModule
 from app.modules.tenancy.models.store_platform import StorePlatform
+from app.modules.tenancy.schemas.auth import UserContext
 from main import app
-from models.schema.auth import UserContext
 
 # ============================================================================
 # Fixtures

app/modules/marketplace/tests/unit/test_store_page_routes.py

@@ -19,7 +19,7 @@ from app.modules.marketplace.routes.pages.store import (
     store_marketplace_page,
     store_onboarding_page,
 )
-from models.schema.auth import UserContext
+from app.modules.tenancy.schemas.auth import UserContext
 
 
 def _make_user_context(store_id: int = 1, store_code: str = "teststore") -> UserContext: