feat(P4): transparent terraform + feature flags + run_platform.sh split (REQ-233..238)

Create run_codegen.sh (pre-TF: env check, validate, resolve, adapt).
Create run_postapply.sh (post-TF: Checkov, confidence, HITL, outbox, SSM, uptime).
Add variable 'enabled' (bool, default true) + count=var.enabled?1:0 to all 12
L1 modules (alb, cloudfront, ecr, ecs-cluster, ecs-service, iam-role, kms-key,
rds, s3, uptime, vpc, waf). Fix all cross-resource references with [0] indexing.
Update interface.json for all modules to declare 'enabled' input.
Fix stale artifact path /tmp/acdl_platform_run_v18 → /tmp/nova_platform_run (REQ-238).
run_platform.sh remains as backward-compat shim for local-dev usage.

---ci---
project: acdl
phase: 4
milestone: v1.20
status: execute
requirements: [REQ-233, REQ-234, REQ-235, REQ-236, REQ-237, REQ-238]
---/ci---

modules/l1/rds/terraform/main.tf

@@ -5,6 +5,7 @@ resource "aws_db_subnet_group" "this" {
 }
 
 resource "aws_db_instance" "this" {
+  count = var.enabled ? 1 : 0
   engine               = var.engine
   engine_version       = var.engine_version
   instance_class       = var.instance_class

modules/l1/rds/terraform/outputs.tf

@@ -1,9 +1,9 @@
 output "db_endpoint" {
-  value       = aws_db_instance.this.endpoint
+  value       = aws_db_instance.this[0].endpoint
   description = "The RDS instance endpoint."
 }
 
 output "db_arn" {
-  value       = aws_db_instance.this.arn
+  value       = aws_db_instance.this[0].arn
   description = "The RDS instance ARN."
 }

modules/l1/rds/terraform/variables.tf

@@ -64,3 +64,9 @@ variable "subnet_ids" {
   description = "Comma-separated subnet IDs for the DB subnet group (VPC-dependent)."
   default     = ""
 }
+
+variable "enabled" {
+  type        = bool
+  description = "Feature flag: enable/disable this module. Set to false to skip resource creation."
+  default     = true
+}