Update item info and sales order pages with new components and functionality

- Updated the item information page to include category code to label conversion for better data representation.
- Enhanced the sales order page by integrating a fullscreen dialog for improved user experience during order registration and editing.
- Added dynamic loading of delivery options based on selected customers to streamline the order process.
- Introduced a new FullscreenDialog component for consistent fullscreen behavior across modals.
- Implemented validation utilities for form fields to ensure data integrity during user input.

frontend/lib/utils/validation.ts

@@ -0,0 +1,92 @@
+/**
+ * 공통 폼 유효성 검증 + 자동 포맷팅 유틸리티
+ */
+
+// --- 자동 포맷팅 ---
+
+// 전화번호: 숫자만 추출 → 자동 하이픈
+// 010-1234-5678 / 02-1234-5678 / 031-123-4567
+export function formatPhone(value: string): string {
+  const nums = value.replace(/\D/g, "").slice(0, 11);
+  if (nums.startsWith("02")) {
+    if (nums.length <= 2) return nums;
+    if (nums.length <= 5) return `${nums.slice(0, 2)}-${nums.slice(2)}`;
+    if (nums.length <= 9) return `${nums.slice(0, 2)}-${nums.slice(2, 5)}-${nums.slice(5)}`;
+    return `${nums.slice(0, 2)}-${nums.slice(2, 6)}-${nums.slice(6)}`;
+  }
+  if (nums.length <= 3) return nums;
+  if (nums.length <= 7) return `${nums.slice(0, 3)}-${nums.slice(3)}`;
+  return `${nums.slice(0, 3)}-${nums.slice(3, 7)}-${nums.slice(7)}`;
+}
+
+// 사업자번호: 000-00-00000
+export function formatBusinessNumber(value: string): string {
+  const nums = value.replace(/\D/g, "").slice(0, 10);
+  if (nums.length <= 3) return nums;
+  if (nums.length <= 5) return `${nums.slice(0, 3)}-${nums.slice(3)}`;
+  return `${nums.slice(0, 3)}-${nums.slice(3, 5)}-${nums.slice(5)}`;
+}
+
+// 필드명으로 자동 포맷팅
+export function formatField(fieldName: string, value: string): string {
+  switch (fieldName) {
+    case "contact_phone":
+    case "phone":
+    case "cell_phone":
+      return formatPhone(value);
+    case "business_number":
+      return formatBusinessNumber(value);
+    default:
+      return value;
+  }
+}
+
+// --- 유효성 검증 ---
+
+export function validatePhone(value: string): string | null {
+  if (!value) return null;
+  const nums = value.replace(/\D/g, "");
+  if (nums.length < 9) return "전화번호를 끝까지 입력해주세요";
+  return null;
+}
+
+export function validateEmail(value: string): string | null {
+  if (!value) return null;
+  if (!/^[^\s@]+@[^\s@]+\.[^\s@]+$/.test(value)) return "올바른 이메일 형식이 아닙니다";
+  return null;
+}
+
+export function validateBusinessNumber(value: string): string | null {
+  if (!value) return null;
+  const nums = value.replace(/\D/g, "");
+  if (nums.length < 10) return "사업자번호를 끝까지 입력해주세요";
+  return null;
+}
+
+export function validateField(fieldName: string, value: string): string | null {
+  if (!value) return null;
+  switch (fieldName) {
+    case "contact_phone":
+    case "phone":
+    case "cell_phone":
+      return validatePhone(value);
+    case "email":
+      return validateEmail(value);
+    case "business_number":
+      return validateBusinessNumber(value);
+    default:
+      return null;
+  }
+}
+
+export function validateForm(
+  data: Record<string, any>,
+  fields: string[]
+): Record<string, string> {
+  const errors: Record<string, string> = {};
+  for (const field of fields) {
+    const error = validateField(field, data[field] || "");
+    if (error) errors[field] = error;
+  }
+  return errors;
+}