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

docs/ARCHITECTURE.md

@@ -30,11 +30,12 @@ requires a class to generate field validation, JSON (de)serialization, and
 the OpenAPI schema FastAPI exposes at `/docs`. Each class is a **data
 contract**, not behavior - no methods, just typed fields.
 
-### `src/nf_hotel_api/domain/metadata.py` - classes: `RoomType`, `HotelMetadata`
+### `src/nf_hotel_api/domain/metadata.py` - classes: `RoomType`, `Address`, `NearbyEvent`, `HotelMetadata`
 
-Pydantic models for the reference data in `data/hotel_metadata.json`: per room
-type its size, standard price per night and (optional) number of rooms.
-`HotelMetadata.describe()` renders the catalogue as text for the LLM prompt.
+Pydantic models for the reference data in `data/hotel_metadata.json`: address,
+per room type its size, standard price per night and number of rooms, plus the
+nearby Phnom Penh events (date ranges are validated). Public holidays are not
+stored; see `services/public_holidays.py`. `HotelMetadata.describe()` renders it all as text for the LLM prompt.
 
 ## Core (config & security)
 
@@ -85,6 +86,13 @@ standard price, and derives `room_size` and `revenue`. The class keeps these ste
 testable (see `tests/test_cleaning.py`), and lets the whole pipeline be
 swapped out in `ReportService`.
 
+### `src/nf_hotel_api/services/public_holidays.py` - class `PublicHolidayCalendar`
+
+Thin wrapper over the `holidays` package (country `KH`): returns holidays per
+year, looks up a single day, merges consecutive days into `HolidayPeriod`s and
+renders them as text for the LLM prompt. `data/holidays.json` is an export of
+the periods, regenerated by `scripts/update_holidays.py`.
+
 ### `src/nf_hotel_api/services/statistics.py` - class `DescriptiveStatsService`
 
 A single-purpose class computing and JSON-serializing `df.describe()`. It