Add data generation scripts and public holidays service

- Add scripts for generating booking data, building metadata, and
  updating holidays
- Implement public_holidays.py service with holiday lookup functionality
- Update CSV data with expanded hotel booking records
- Add holidays.json dataset for public holiday dates
- Enhance LLM report service with improved formatting
- Update metadata domain model and API dependencies
- Add test coverage for dataset and public holidays

scripts/update_holidays.py

@@ -0,0 +1,55 @@
+"""Regenerates data/holidays.json from the `holidays` package.
+
+The file is an export, not a source of truth: the application reads holidays
+straight from the package (services/public_holidays.py). Run this script to
+refresh the export - after upgrading the package, or when a new year starts:
+
+    .venv/Scripts/python scripts/update_holidays.py
+    .venv/Scripts/python scripts/update_holidays.py --first-year 2022 --last-year 2028
+
+By default it covers 2022 (start of the booking data) up to next year.
+`tests/test_public_holidays.py` fails when the file no longer matches the
+package, which is the signal to re-run this script.
+"""
+import argparse
+import json
+import sys
+from datetime import date
+from pathlib import Path
+
+ROOT = Path(__file__).resolve().parents[1]
+sys.path.insert(0, str(ROOT / "src"))
+
+from nf_hotel_api.services.public_holidays import PublicHolidayCalendar  # noqa: E402
+
+OUTPUT = ROOT / "data" / "holidays.json"
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser(description=__doc__.splitlines()[0])
+    parser.add_argument("--first-year", type=int, default=2022)
+    parser.add_argument("--last-year", type=int, default=date.today().year + 1)
+    parser.add_argument("--country", default="KH", help="ISO country code used by the holidays package")
+    args = parser.parse_args()
+
+    calendar = PublicHolidayCalendar(args.country)
+    document = {
+        "country": calendar.country_code,
+        "source": f"python-holidays {calendar.package_version()}",
+        "first_year": args.first_year,
+        "last_year": args.last_year,
+        "holidays": [
+            {
+                "name": period.name,
+                "start_date": period.start_date.isoformat(),
+                "end_date": period.end_date.isoformat(),
+            }
+            for period in calendar.periods(args.first_year, args.last_year)
+        ],
+    }
+    OUTPUT.write_text(json.dumps(document, indent=2, ensure_ascii=False) + "\n", encoding="utf-8")
+    print(f"wrote {OUTPUT} ({len(document['holidays'])} holiday periods, {args.first_year}-{args.last_year})")
+
+
+if __name__ == "__main__":
+    main()