fix: improve error messages for config file reading

config/customer.go

@@ -17,7 +17,7 @@ type CustomerConfig struct {
 func ReadCustomerConfig(path string) (CustomerConfig, error) {
 	data, err := os.ReadFile(path)
 	if err != nil {
-		return CustomerConfig{}, fmt.Errorf("failed to read file: %w", err)
+		return CustomerConfig{}, fmt.Errorf("failed to read customer configfile: %w", err)
 	}
 
 	var cust CustomerConfig