[FE] Allow no more than two decimal places in the Raise the limit form

[mshkkkkk]

Summary
The form displays the spent amount with two decimal places but allows the user to enter a new limit with four. For example, it shows $0.60 spent, yet 0.6001 and 0.6002 are rejected while 0.6003 is accepted. The user cannot tell which four-digit value will work from the amount shown.
Limit input in this form to cents so the allowed input matches the displayed money format.

Requirements

• Allow at most two digits after the decimal point in the New limit field.
• Show an inline validation message when the user enters more than two digits.
• Do not submit an invalid value.
• Keep the existing checks that the new limit must be higher than the current limit and the amount already spent.
• Continue storing and calculating actual model costs at their existing precision.

Acceptance Criteria

• The New limit field accepts an amount with no decimal places or with one or two decimal places.
• If the user enters three or more decimal places, an inline validation message appears and no request is sent.
• The validation message disappears after the user corrects the value.
• A value with a valid format can be submitted if it also passes the existing budget checks.