Cashu improvements

[lindsaymoralesb]

This PR includes: History UI improvements, Scanner UI improvements, and addition of units and conversion p1.

History UI

History UI improved:

https://github.com/user-attachments/assets/b540d410-deeb-47b8-bd81-4bbd6432eaf6

Scanner UI

Grant permission:

https://github.com/user-attachments/assets/07686d9e-c4b6-416a-a570-6ddbd9862874

Scanner Mobile:

https://github.com/user-attachments/assets/b8a83cb1-d384-43f8-9f05-d3ea1f0137d4

Scanner Desktop:

https://github.com/user-attachments/assets/91b01b6d-3a92-47b3-a295-14f653192739

Scanned data modal:

Units

Units and balance added on mints list, also added mint info modal.

https://github.com/user-attachments/assets/bd20dbd3-2e92-4296-8e1e-e80073cba1cd

Units and balance for each mint:

Change balance unit:

https://github.com/user-attachments/assets/e82e7aee-e7ba-4b01-900b-666132884f25

Use currency on send ecash:

https://github.com/user-attachments/assets/9f92cd82-16b0-4f94-929a-c711a18b4aa6