fix: remove type="number" from amount input, use text input like postal_code

- Follow same pattern as postal_code field in member form
- Ash validates Decimal format automatically
- Text input allows better control and validation feedback

lib/mv_web/live/membership_fee_type_live/form.ex

@@ -42,11 +42,7 @@ defmodule MvWeb.MembershipFeeTypeLive.Form do
 
         <.input
           field={@form[:amount]}
-          type="number"
           label={gettext("Amount")}
-          step="0.01"
-          min="0"
-          phx-debounce="300"
           required
         />