Fix invoice file 500 and pdf.worker MIME error

- Remove stale import of non-existent require_cap_from_token from
  get_invoice_file endpoint — caused ImportError → 500 on every PDF load
- Fix pdf.js worker path from '/pdf.worker.min.mjs' to '/kitchen/pdf.worker.min.mjs'
  in Review.tsx and SearchDefinitions.tsx — worker was being fetched from domain
  root instead of under the /kitchen/ base, causing MIME type rejection

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

frontend/src/components/Review.tsx

@@ -13,7 +13,7 @@ import IngredientModal from './IngredientModal'
 import { IngredientModalResult, LineItemResult } from '../utils/ingredientHelpers'
 
 // Use local worker file from public directory
-pdfjsLib.GlobalWorkerOptions.workerSrc = '/pdf.worker.min.mjs'
+pdfjsLib.GlobalWorkerOptions.workerSrc = '/kitchen/pdf.worker.min.mjs'
 
 // Simple Scale icon SVG component
 const ScaleIcon = ({ style }: { style?: React.CSSProperties }) => (

frontend/src/components/SearchDefinitions.tsx

@@ -15,7 +15,7 @@ import {
 import * as pdfjsLib from 'pdfjs-dist'
 
 // Configure PDF.js worker
-pdfjsLib.GlobalWorkerOptions.workerSrc = '/pdf.worker.min.mjs'
+pdfjsLib.GlobalWorkerOptions.workerSrc = '/kitchen/pdf.worker.min.mjs'
 
 interface ProductDefinition {
   id: number