Add Terraform AWS infrastructure and enhanced CI/CD pipeline (FRE-4574)

- Terraform modules: VPC, ECS Fargate, RDS PostgreSQL, ElastiCache Redis, S3, Secrets Manager, CloudWatch
- Multi-environment support: staging and production configs
- ECS auto-scaling: CPU-based scaling with configurable min/max
- CI/CD: pnpm caching, Docker Buildx, Trivy security scanning, Terraform plan on PR
- Deploy: ECS service updates with automatic rollback on health check failure
- Backup: automated RDS snapshots, S3 versioning, ElastiCache snapshots
- Monitoring: CloudWatch dashboards, CPU/memory/5xx alarms
- Rollback script for manual service rollback
- Infrastructure documentation with architecture overview

infra/variables.tf

@@ -0,0 +1,116 @@
+variable "aws_region" {
+  description = "AWS region"
+  type        = string
+  default     = "us-east-1"
+}
+
+variable "environment" {
+  description = "Deployment environment"
+  type        = string
+  validation {
+    condition     = contains(["dev", "staging", "production"], var.environment)
+    error_message = "Environment must be one of: dev, staging, production."
+  }
+}
+
+variable "project_name" {
+  description = "Project name for resource naming"
+  type        = string
+  default     = "shieldai"
+}
+
+variable "vpc_cidr" {
+  description = "CIDR block for VPC"
+  type        = string
+  default     = "10.0.0.0/16"
+}
+
+variable "az_count" {
+  description = "Number of availability zones"
+  type        = number
+  default     = 2
+}
+
+variable "db_name" {
+  description = "RDS database name"
+  type        = string
+  default     = "shieldai"
+}
+
+variable "db_instance_class" {
+  description = "RDS instance class"
+  type        = string
+  default     = "db.t3.medium"
+}
+
+variable "db_multi_az" {
+  description = "Enable Multi-AZ deployment"
+  type        = bool
+  default     = true
+}
+
+variable "db_backup_retention" {
+  description = "RDS backup retention period in days"
+  type        = number
+  default     = 7
+}
+
+variable "elasticache_node_type" {
+  description = "ElastiCache node type"
+  type        = string
+  default     = "cache.t3.medium"
+}
+
+variable "elasticache_num_nodes" {
+  description = "Number of ElastiCache nodes"
+  type        = number
+  default     = 2
+}
+
+variable "services" {
+  description = "ECS services to deploy"
+  type = map(object({
+    cpu    = number
+    memory = number
+    port   = number
+  }))
+  default = {
+    api = {
+      cpu    = 512
+      memory = 1024
+      port   = 3000
+    }
+    darkwatch = {
+      cpu    = 256
+      memory = 512
+      port   = 3001
+    }
+    spamshield = {
+      cpu    = 256
+      memory = 512
+      port   = 3002
+    }
+    voiceprint = {
+      cpu    = 512
+      memory = 1024
+      port   = 3003
+    }
+  }
+}
+
+variable "container_images" {
+  description = "Container image tags per service"
+  type        = map(string)
+  default = {
+    api        = "latest"
+    darkwatch  = "latest"
+    spamshield = "latest"
+    voiceprint = "latest"
+  }
+}
+
+variable "secrets" {
+  description = "Secrets to store in AWS Secrets Manager"
+  type        = map(string)
+  default     = {}
+}