feat(dashboard): reconstruct backend router/service, register route, fix suppliers NameError

backend/app/routers/__init__.py

@@ -4,6 +4,7 @@ from app.routers import (
     auth,
     brand_materials,
     brands,
+    dashboard,
     drafts,
     files,
     inventory,
@@ -53,6 +54,7 @@ ROUTERS = [
     inventory.router,
     pm.router,
     project_transfers.router,
+    dashboard.router,
     users.router,
     drafts.router,
 ]