add missing variable to lambda variables

deployment/terraform/lambda/audit_generator/variables.tf

@@ -3,6 +3,12 @@ variable "stage" {
   type        = string
 }
 
+variable "lambda_name" {
+  description = "Lambda function name (passed by the deploy workflow)"
+  type        = string
+  default     = "audit_generator"
+}
+
 variable "ecr_repo_url" {
   type        = string
   description = "ECR repository URL (no tag, no digest)"