feat: 운송장 번호 자동 정리 + 날짜에 요일 표시

- 운송장 번호 입력 시 공백/하이픈 실시간 제거
- 택배 카드 날짜에 요일 추가 (월, 화, ...)

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/components/ParcelCard.jsx

@@ -1,5 +1,6 @@
 import { useQuery } from "@tanstack/react-query";
 import dayjs from "dayjs";
+import "dayjs/locale/ko";
 import StatusBadge from "./StatusBadge";
 import { fetchCarriers } from "@/api/parcels";
 
@@ -34,7 +35,7 @@ function ParcelCard({ parcel, onClick }) {
 
         <div className="flex items-center justify-between">
           <span className="text-xs lg:text-sm text-gray-400">
-            {dayjs(parcel.created_at).format("YYYY.MM.DD")}
+            {dayjs(parcel.created_at).locale("ko").format("YYYY.MM.DD (dd)")}
           </span>
           <StatusBadge status={parcel.status} />
         </div>

frontend/src/components/ParcelForm.jsx

@@ -34,7 +34,7 @@ function ParcelForm({ onClose }) {
     setError("");
     mutation.mutate({
       carrierId,
-      trackingNumber: trackingNumber.replace(/\s/g, ""),
+      trackingNumber: trackingNumber.replace(/[\s\-]/g, ""),
       label: label || undefined,
     });
   };
@@ -69,7 +69,7 @@ function ParcelForm({ onClose }) {
           <input
             type="text"
             value={trackingNumber}
-            onChange={(e) => setTrackingNumber(e.target.value)}
+            onChange={(e) => setTrackingNumber(e.target.value.replace(/[\s\-]/g, ""))}
             placeholder="운송장 번호 입력"
             className="w-full border border-gray-300 rounded-lg px-3 lg:px-4 py-2 lg:py-2.5 text-sm lg:text-base focus:outline-none focus:ring-2 focus:ring-primary/30 focus:border-primary"
             required