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

tests/test_public_holidays.py

@@ -0,0 +1,65 @@
+from datetime import date
+
+from nf_hotel_api.services.public_holidays import PublicHolidayCalendar
+
+
+def test_for_years_covers_the_requested_years_in_date_order():
+    result = PublicHolidayCalendar().for_years(2022, 2023)
+
+    assert list(result) == sorted(result)
+    assert {d.year for d in result} == {2022, 2023}
+
+
+def test_khmer_new_year_and_water_festival_2024_match_the_official_calendar():
+    calendar = PublicHolidayCalendar().for_years(2024, 2024)
+
+    for day in (date(2024, 4, 13), date(2024, 4, 16)):
+        assert "Khmer New Year" in calendar[day]
+    for day in (date(2024, 11, 14), date(2024, 11, 16)):
+        assert "Water Festival" in calendar[day]
+    assert "Peace Day" in calendar[date(2024, 12, 29)]
+
+
+def test_name_on_returns_none_for_a_normal_day():
+    calendar = PublicHolidayCalendar()
+
+    assert calendar.name_on(date(2024, 8, 14)) is None
+    assert "Pchum Ben" in calendar.name_on(date(2025, 9, 22))
+
+
+def test_describe_merges_consecutive_days_into_a_range():
+    text = PublicHolidayCalendar().describe(2024, 2024)
+
+    assert "- 2024-04-13 to 2024-04-16: Khmer New Year's Day" in text
+    assert "- 2024-11-14 to 2024-11-16: Water Festival" in text
+    assert "- 2024-01-01: International New Year Day" in text
+
+
+def test_holidays_json_is_an_up_to_date_export_of_the_package():
+    """Fails when the `holidays` package changed: re-run scripts/update_holidays.py."""
+    import json
+    from pathlib import Path
+
+    document = json.loads(
+        (Path(__file__).resolve().parents[1] / "data" / "holidays.json").read_text(encoding="utf-8")
+    )
+    calendar = PublicHolidayCalendar(document["country"])
+
+    expected = [
+        {"name": p.name, "start_date": p.start_date.isoformat(), "end_date": p.end_date.isoformat()}
+        for p in calendar.periods(document["first_year"], document["last_year"])
+    ]
+
+    assert document["holidays"] == expected
+
+
+def test_holidays_json_covers_the_booking_years():
+    import json
+    from pathlib import Path
+
+    document = json.loads(
+        (Path(__file__).resolve().parents[1] / "data" / "holidays.json").read_text(encoding="utf-8")
+    )
+
+    assert document["first_year"] <= 2022
+    assert document["last_year"] >= 2025