throttle polling outside business hours

Single DAG, single 30-min schedule instead of 5-min or two separate
DAGs. run_sync() itself decides whether to do real work: always during
business hours (default 07:00-17:00 WIB), otherwise only once per
EDOXID_OFF_HOURS_INTERVAL_MINUTES (default 120) tracked via a
last_full_sync timestamp in the sqlite state. Off-hours skips return
immediately without touching DB/Calendar/Gmail at all.

scripts/edoxid_calendar_state_store.py

@@ -25,6 +25,23 @@ class StateStore:
             )
             """
         )
+        self._conn.execute(
+            "CREATE TABLE IF NOT EXISTS sync_meta (key TEXT PRIMARY KEY, value TEXT NOT NULL)"
+        )
+        self._conn.commit()
+
+    def get_last_full_sync(self) -> datetime | None:
+        row = self._conn.execute(
+            "SELECT value FROM sync_meta WHERE key = 'last_full_sync'"
+        ).fetchone()
+        return datetime.fromisoformat(row[0]) if row else None
+
+    def set_last_full_sync(self, when: datetime) -> None:
+        self._conn.execute(
+            "INSERT INTO sync_meta (key, value) VALUES ('last_full_sync', ?) "
+            "ON CONFLICT(key) DO UPDATE SET value = excluded.value",
+            (when.isoformat(),),
+        )
         self._conn.commit()
 
     def close(self) -> None: