feat: add ItemOverviewDto for enriched item data in items list

feat: implement CustomerDetailPage for detailed customer view and editing

feat: create CustomersPage for listing and managing customers with filters

feat: add ColumnsMenu component for customizable table columns visibility

feat: implement CSV export functionality for data download

feat: add customer code generation logic for unique customer identifiers

Frontend/erp-system/lib/customer-code.ts

@@ -0,0 +1,18 @@
+/** First word of the name, uppercased and stripped to alphanumerics — falls back to "CU"
+ * so an empty/punctuation-only name still yields a usable base. Mirrors the vendor code
+ * generator (lib/vendor-code.ts). */
+function customerCodeBase(name: string): string {
+  const firstWord = name.trim().split(/\s+/)[0] ?? ""
+  const cleaned = firstWord.toUpperCase().replace(/[^A-Z0-9]/g, "")
+  return cleaned.slice(0, 10) || "CU"
+}
+
+/** Appends a numeric suffix until the code doesn't collide with an existing one — the
+ * backend enforces global uniqueness but has no generation of its own. */
+export function generateCustomerCode(name: string, existingCodes: string[]): string {
+  const base = `CU-${customerCodeBase(name)}`
+  if (!existingCodes.includes(base)) return base
+  let suffix = 2
+  while (existingCodes.includes(`${base}${suffix}`)) suffix += 1
+  return `${base}${suffix}`
+}