Remove '일' suffix from Korean calendar day numbers

Modified formatDay function in both calendar components:
- For Korean locale (ko), display only the day number (e.g., '10' instead of '10일')
- For other locales, use default toLocaleString formatting

Changes:
- nice-calendar.tsx: Updated formatDay to check currentLocale === 'ko'
- nice-calendar-month.tsx: Updated formatDay to check currentLocale === 'ko'

🤖 Generated with [Claude Code](https://claude.com/claude-code)

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

src/shared/ui/calendar/nice-calendar-month.tsx

@@ -77,6 +77,10 @@ const NiceCalendarMonth = ({
     });
   };
   const formatDay = (locale: string | undefined, date: Date) => {
+    // For Korean locale, return only the day number without '일'
+    if (currentLocale === 'ko') {
+      return date.getDate().toString();
+    }
     return date.toLocaleString(currentLocale, {
       day: 'numeric'
     });

src/shared/ui/calendar/nice-calendar.tsx

@@ -83,6 +83,10 @@ const NiceCalendar = ({
     });
   };
   const formatDay = (locale: string | undefined, date: Date) => {
+    // For Korean locale, return only the day number without '일'
+    if (currentLocale === 'ko') {
+      return date.getDate().toString();
+    }
     return date.toLocaleString(currentLocale, {
       day: 'numeric'
     });