Mobile view overhaul: bottom nav, card inventory, camera scanner, PWA

Replace the cramped horizontal sidebar with a 5-tab bottom nav (Home,
Inventory, Scan, Custody, More) with an elevated scan button. Convert
the 10-column inventory table to card-based list on mobile with
scrollable filter pills and long-press selection. Add full-screen
camera barcode scanner using html5-qrcode with post-scan action sheet.
Set up PWA with vite-plugin-pwa for add-to-home-screen. Convert modals
to bottom sheets, add pull-to-refresh, safe-area padding, and iOS
input zoom fix.

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

web/src/components/ScanField.tsx

@@ -125,7 +125,7 @@ export function ScanField({
   );
 }
 
-function lookup(
+export function lookup(
   trimmed: string,
   items: Item[],
   products?: Product[],