- Implement NepaliCurrencyField for model-level currency handling.
- Add format_nepali_currency utility with Lakhs/Crores comma formatting and decimal support.
- Implement number_to_nepali_words and english_to_nepali_unicode helper functions.
- Add nepali_currency, nepali_words, and nepali_unicode template filters.
- Enhance REST API (DRF) support:
- Added NepaliCurrencySerializerField for formatted currency output.
- Added NepaliLocalizedSerializerMixin for automatic Devanagari field generation.
- Added flexible NepaliCurrencyRangeFilter and NepaliDateRangeFilter.
- Integrated automatic currency formatting into NepaliModelAdmin.
- Expanded the example demo app with a Transaction model and updated filters.
- Added comprehensive unit tests for formatting, models, and API components.
- Updated documentation (README.md and todo.md) to reflect new features.