- Updated import statements in `mooc/models/__init__.py` to use parentheses for clarity.
- Refactored `mooc/models/core.py` to replace `UnsignedInteger` with `INTEGER(unsigned=True)` for better compatibility.
- Introduced new `MobileNumber` model in `mooc/models/mobile_number.py` with appropriate fields.
- Added `ProfileFields` model in `mooc/models/profile_fields.py` with detailed attributes.
- Updated schemas in `mooc/schemas/mobile_number.py` and `mooc/schemas/profile_fields.py` to reflect model changes and improve naming conventions.
- Ensured all models and schemas are consistent with naming and data types.
