v2.10.0: \uc815\ubd80 \ud2b9\uc77c\uc815\ubcf4 API \uc5f0\ub3d9 + \uc77c \uc790\ub3d9 \ub3d9\uae30\ud654

\uacf5\uacf5\ub370\uc774\ud130\ud3ec\ud138 \ud55c\uad6d\ucc9c\ubb38\uc5f0\uad6c\uc6d0 \ud2b9\uc77c\uc815\ubcf4 API\ub85c \uc784\uc2dc\uacf5\ud734\uc77c\uae4c\uc9c0
\uc815\ubd80 \uacf5\uc778 \ub370\uc774\ud130\ub85c \ubcf4\uac15. holidays \ud328\ud0a4\uc9c0\ub294 fallback.

- utils/holiday_api.py: getRestDeInfo \uc5d4\ub4dc\ud3ec\uc778\ud2b8 + \uc751\ub2f5 \ud30c\uc11c (\ub2e8\uc77c/\ub2e4\uc218 item)
- Database.add_korean_holidays_from_api(year) + add_korean_holidays_auto fallback chain
- migrate_v290_holidays_auto_sync: \uc77c 1\ud68c \ubc31\uadf8\ub77c\uc6b4\ub4dc \ub3d9\uae30\ud654
  (sentinel holidays_synced_date, daemon thread, CLOCKOUT_DISABLE_HOLIDAY_SYNC env var)
- Settings UI \uc548\ub0b4\ubb38 \uc5c5\ub370\uc774\ud2b8

Tests: tests/test_holiday_api.py 14\uac1c + conftest.py + 175\u2192189 pytest \uc804\ubd80 green
\ud1b5\ud569 \uc2dc\ub098\ub9ac\uc624 53/53 green

\uc8fc\uc758: \ud0a4 \ud65c\uc6a9\uae30\uac04 \uc2dc\uc791 \uc9c1\ud6c4 (2026-05-01) propagation \uc73c\ub85c 401 \uac00\ub2a5,
fallback \uacbd\ub85c\uac00 \ud574\ub2f9 \uc0ac\ub840 \ucee4\ubc84 \u2014 \uadfc\ub85c\uc790\uc758 \ub0a0 \ud3ec\ud568 22\uac1c \ud734\uc77c \uc790\ub3d9 \ub4f1\ub85d \ud655\uc778

ui/settings_view.py

@@ -688,10 +688,11 @@ class SettingsView(QDialog):
             "한국 공휴일 자동 추가",
             f"{target_label} 한국 공휴일을 자동으로 등록하시겠습니까?\n\n"
             "포함:\n"
-            "• 양력 공휴일 (신정/삼일절/어린이날 등)\n"
+            "• 양력 공휴일 (신정/삼일절/어린이날/근로자의 날 등)\n"
             "• 음력 명절 (설날 연휴/추석 연휴/석가탄신일)\n"
             "• 정부 지정 대체·임시공휴일\n\n"
-            "※ 외부 'holidays' 패키지 사용 (requirements.txt 참조)",
+            "※ 1차: 공공데이터포털 특일정보 API (정부 공인, 임시공휴일 포함)\n"
+            "※ 2차 fallback: 'holidays' 패키지 (오프라인)",
             QMessageBox.Yes | QMessageBox.No
         )
         if reply != QMessageBox.Yes: