While prescribing medicine, the Unit field should be pre-filled with "Days" by default. However, the user should still have the flexibility to change the unit if required.

Steps to Reproduce:

1. Login to the application
2. Navigate to Prescription / Medicine section
3. Add a new medicine
4. Observe the Unit field

Actual Result:

• Unit field is either blank or not set to "Days" by default

Expected Result:

• Unit field should be auto-selected as "Days" by default
• User should be able to change it to other options (e.g., Weeks, Months, etc.)