feat: use batch save for invoice items

src/stores/invoices.ts

@@ -112,15 +112,20 @@ export const useInvoicesStore = defineStore('invoices', () => {
     }
   }
 
-  async function saveInvoiceItems(invoiceId: number, items: { description: string; quantity: number; unit_price: number }[]): Promise<void> {
-    for (const item of items) {
-      await createInvoiceItem({
-        invoice_id: invoiceId,
-        description: item.description,
-        quantity: item.quantity,
-        rate: item.unit_price,
-        amount: item.quantity * item.unit_price,
+  async function saveInvoiceItems(invoiceId: number, items: { description: string; quantity: number; unit_price: number; time_entry_id?: number }[]): Promise<void> {
+    try {
+      await invoke('save_invoice_items_batch', {
+        invoiceId,
+        items: items.map(item => ({
+          description: item.description,
+          quantity: item.quantity,
+          unit_price: item.unit_price,
+          time_entry_id: item.time_entry_id || null,
+        })),
       })
+    } catch (error) {
+      handleInvokeError(error, 'Failed to save invoice items')
+      throw error
     }
   }