feat: add AI Dental Shopping section with sidebar nav and Login Info page

- Add AI Dental Shopping to sidebar with Search/Tag and Login Info sub-pages
- Build full-stack Login Info CRUD: save vendor name, website, username, password per user
- Add ShoppingVendor Prisma model, run db push, regenerate client and Zod schemas
- Add storage layer, REST API at /api/shopping-vendors/, and frontend table with add/edit/delete modal

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

apps/Backend/src/routes/index.ts

@@ -32,6 +32,7 @@ import officeContactRoutes from "./office-contact";
 import procedureTimeslotRoutes from "./procedure-timeslot";
 import insuranceContactsRoutes from "./insurance-contacts";
 import commissionsRoutes from "./commissions";
+import shoppingVendorsRoutes from "./shopping-vendors";
 
 const router = Router();
 
@@ -68,5 +69,6 @@ router.use("/office-contact", officeContactRoutes);
 router.use("/procedure-timeslot", procedureTimeslotRoutes);
 router.use("/insurance-contacts", insuranceContactsRoutes);
 router.use("/commissions", commissionsRoutes);
+router.use("/shopping-vendors", shoppingVendorsRoutes);
 
 export default router;