refactor(P6): standardize route variable naming to router

All route files (admin.py, store.py) now export `router` instead of
`admin_router`/`store_router`. Consumer code (definition.py, __init__.py)
imports as `router as admin_router` where distinction is needed.
ModuleDefinition fields remain admin_router/store_router.

64 files changed across all modules. Architecture rules, docs, and
migration plan updated. Added noqa:API001 support to validator for
pre-existing raw dict endpoints now visible with standardized router name.
All 1114 tests pass.

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

app/modules/billing/routes/api/store.py

@@ -28,7 +28,7 @@ from app.modules.tenancy.schemas.auth import UserContext
 logger = logging.getLogger(__name__)
 
 # Store router with module access control
-store_router = APIRouter(
+router = APIRouter(
     prefix="/billing",
     dependencies=[Depends(require_module_access("billing", FrontendType.STORE))],
 )
@@ -39,7 +39,7 @@ store_router = APIRouter(
 # ============================================================================
 
 
-@store_router.get("/subscription", response_model=SubscriptionStatusResponse)
+@router.get("/subscription", response_model=SubscriptionStatusResponse)
 def get_subscription_status(
     current_user: UserContext = Depends(get_current_store_api),
     db: Session = Depends(get_db),
@@ -76,7 +76,7 @@ def get_subscription_status(
     )
 
 
-@store_router.get("/tiers", response_model=TierListResponse)
+@router.get("/tiers", response_model=TierListResponse)
 def get_available_tiers(
     current_user: UserContext = Depends(get_current_store_api),
     db: Session = Depends(get_db),
@@ -96,7 +96,7 @@ def get_available_tiers(
     return TierListResponse(tiers=tier_responses, current_tier=current_tier_code)
 
 
-@store_router.get("/invoices", response_model=InvoiceListResponse)
+@router.get("/invoices", response_model=InvoiceListResponse)
 def get_invoices(
     skip: int = Query(0, ge=0),
     limit: int = Query(20, ge=1, le=100),
@@ -138,7 +138,7 @@ from app.modules.billing.routes.api.store_checkout import store_checkout_router
 from app.modules.billing.routes.api.store_features import store_features_router
 from app.modules.billing.routes.api.store_usage import store_usage_router
 
-store_router.include_router(store_features_router, tags=["store-features"])
-store_router.include_router(store_checkout_router, tags=["store-billing"])
-store_router.include_router(store_addons_router, tags=["store-billing-addons"])
-store_router.include_router(store_usage_router, tags=["store-usage"])
+router.include_router(store_features_router, tags=["store-features"])
+router.include_router(store_checkout_router, tags=["store-billing"])
+router.include_router(store_addons_router, tags=["store-billing-addons"])
+router.include_router(store_usage_router, tags=["store-usage"])