feat(calendar): show regional holidays and observances

public/locales/ja.json

@@ -367,7 +367,47 @@
     "emptyDay": "この日の記録はありません。",
     "openToday": "記憶を書く",
     "writeMemory": "記憶を追加",
-    "openTasks": "タスクを開く"
+    "openTasks": "タスクを開く",
+    "holidayCountry": "国・地域",
+    "autoCountry": "自動（{country}）",
+    "publicHoliday": "祝日",
+    "festival": "記念日",
+    "workingDay": "勤務日",
+    "observed": "振替休日",
+    "estimated": "日付は暫定",
+    "workingWeekend": "週末の振替出勤日",
+    "loadingHolidays": "祝日を読み込み中…",
+    "holidayUnavailable": "祝日データを取得できません。",
+    "retryHolidays": "再試行",
+    "holidaySource": "祝日データ",
+    "outsideRange": "祝日データは2024～2030年に対応しています。",
+    "festivals": {
+      "valentine": "バレンタインデー",
+      "earth": "アースデー",
+      "halloween": "ハロウィーン",
+      "christmasEve": "クリスマスイブ",
+      "teachers": "教師の日"
+    },
+    "holidayNames": {
+      "New Year's Day": "元日",
+      "Chinese New Year (Spring Festival)": "春節",
+      "Chinese New Year": "春節",
+      "Chinese New Year's Eve": "大晦日（旧暦）",
+      "Tomb-Sweeping Day": "清明節",
+      "Labor Day": "労働者の日",
+      "Dragon Boat Festival": "端午節",
+      "Mid-Autumn Festival": "中秋節",
+      "National Day": "国慶節",
+      "Christmas Day": "クリスマス",
+      "Christmas Eve": "クリスマスイブ",
+      "Good Friday": "聖金曜日",
+      "Easter Monday": "イースターマンデー",
+      "Peace Memorial Day": "平和記念日",
+      "Children's Day": "こどもの日",
+      "Constitution Day": "憲法記念日",
+      "Confucius' Birthday": "孔子誕生日"
+    },
+    "holidayCaveat": "日付は変更される場合があります。現地の公式発表をご確認ください。"
   },
   "tasks": {
     "eyebrow": "目標とタスク",