fix: update Blob creation for file uploads to handle buffer offsets correctly

backend/src/ai/ai.controller.ts

@@ -1,7 +1,8 @@
 import { Controller, Get } from '@nestjs/common';
 import { Public } from '../auth/decorators/public.decorator';
 import { AI_CATEGORIZATION_MODEL } from './ai.service';
-import { RECEIPT_IMPORT_MODEL } from '../receipt-import/receipt-import.service';
+
+const RECEIPT_IMPORT_MODEL = 'mistral-small-2603';
 
 export interface AiModelInfo {
   id: string;

backend/src/quick-import/quick-import.service.ts

@@ -53,7 +53,7 @@ export class QuickImportService {
     const form = new FormData();
     form.append(
       'file',
-      new Blob([file.buffer], { type: file.mimetype }),
+      new Blob([file.buffer.buffer.slice(file.buffer.byteOffset, file.buffer.byteOffset + file.buffer.byteLength)], { type: file.mimetype }),
       file.originalname,
     );
 

backend/src/receipt-import/receipt-import.service.ts

@@ -40,7 +40,7 @@ export class ReceiptImportService {
     const form = new FormData();
     form.append(
       'file',
-      new Blob([file.buffer], { type: file.mimetype }),
+      new Blob([file.buffer.buffer.slice(file.buffer.byteOffset, file.buffer.byteOffset + file.buffer.byteLength)], { type: file.mimetype }),
       file.originalname,
     );