fix: remove unused validate_amount_format function

- Function was removed but definition remained
- Ash handles Decimal validation automatically

lib/mv_web/live/membership_fee_type_live/form.ex

@@ -323,34 +323,6 @@ defmodule MvWeb.MembershipFeeTypeLive.Form do
     assign(socket, form: to_form(form))
   end
 
-  # Validates amount format and cleans invalid characters
-  defp validate_amount_format(params) do
-    case Map.get(params, "amount") do
-      nil -> params
-      "" -> params
-      amount_str when is_binary(amount_str) ->
-        # Check if it's a valid number format
-        case Decimal.parse(amount_str) do
-          {_decimal, ""} ->
-            # Valid decimal
-            params
-
-          {_decimal, _rest} ->
-            # Has trailing characters - invalid, but let Ash handle validation
-            params
-
-          :error ->
-            # Not a valid number - try to clean it up
-            # Remove non-numeric characters except decimal point
-            cleaned = String.replace(amount_str, ~r/[^\d.]/, "")
-            Map.put(params, "amount", cleaned)
-        end
-
-      _ ->
-        params
-    end
-  end
-
   # Helper to extract existing form values to preserve them when only one field changes
   defp get_existing_form_values(form) do
     # Extract values directly from form fields to get current state