fix(6): fix TypeScript type consistency issues

- Make Item.id required (items from DB always have id)
- Use shared Item type from db.ts in QuantityAdjustmentModal
- Show full npm build output instead of silencing errors
- Ensures all modals use consistent type definitions

frontend/lib/db.ts

@@ -1,7 +1,7 @@
 import Dexie, { Table } from 'dexie';
 
 export interface Item {
-  id?: number;
+  id: number;
   barcode: string;
   name: string;
   category: string;