feat: integrate barcode scanning functionality and enhance Appwrite setup

- Added a new `barcode_products` collection to the Appwrite setup for managing barcode data.
- Implemented barcode scanning feature with a dedicated modal for scanning and adding products.
- Introduced new components for barcode product preview and management.
- Updated the setup script to seed verified barcode products from a JSON file.
- Enhanced the application state management to handle barcode-related actions and user interactions.

src/lib/userBarcodeMappings.ts

@@ -0,0 +1,63 @@
+import { normalizeBarcode } from "./barcodeLookup";
+import type { BarcodeProductDraft, UserBarcodeMapping } from "../types";
+
+const STORAGE_PREFIX = "red-bull-barcode-mappings:v1";
+
+export function loadUserBarcodeMappings(userId: string) {
+  const raw = localStorage.getItem(storageKey(userId));
+  if (!raw) return [];
+
+  try {
+    const parsed: unknown = JSON.parse(raw);
+    if (!Array.isArray(parsed)) return [];
+    return parsed.filter(isUserBarcodeMapping);
+  } catch {
+    return [];
+  }
+}
+
+export function saveUserBarcodeMappings(userId: string, mappings: UserBarcodeMapping[]) {
+  localStorage.setItem(storageKey(userId), JSON.stringify(mappings));
+}
+
+export function upsertUserBarcodeMapping(
+  userId: string,
+  barcodeValue: string,
+  product: BarcodeProductDraft,
+) {
+  const barcode = normalizeBarcode(barcodeValue);
+  const now = new Date().toISOString();
+  const mappings = loadUserBarcodeMappings(userId);
+  const existing = mappings.find((mapping) => mapping.barcode === barcode);
+  const nextMapping: UserBarcodeMapping = {
+    ...product,
+    barcode,
+    createdAt: existing?.createdAt ?? now,
+    updatedAt: now,
+  };
+  const nextMappings = existing
+    ? mappings.map((mapping) => (mapping.barcode === barcode ? nextMapping : mapping))
+    : [...mappings, nextMapping];
+
+  saveUserBarcodeMappings(userId, nextMappings);
+  return nextMapping;
+}
+
+function storageKey(userId: string) {
+  return `${STORAGE_PREFIX}:${userId}`;
+}
+
+function isUserBarcodeMapping(value: unknown): value is UserBarcodeMapping {
+  if (!value || typeof value !== "object") return false;
+  const mapping = value as Partial<UserBarcodeMapping>;
+  return (
+    typeof mapping.barcode === "string" &&
+    typeof mapping.flavourName === "string" &&
+    typeof mapping.sizeMl === "number" &&
+    typeof mapping.pricePerCan === "number" &&
+    typeof mapping.createdAt === "string" &&
+    typeof mapping.updatedAt === "string" &&
+    (mapping.sugarFree === undefined || typeof mapping.sugarFree === "boolean") &&
+    (mapping.caffeineMgPerCan === undefined || typeof mapping.caffeineMgPerCan === "number")
+  );
+}