feat: Terraform Foundation - AWS Landing Zone

Enterprise-grade multi-tenant AWS cloud foundation.

Modules:
- GitHub OIDC for keyless CI/CD authentication
- IAM account settings and security baseline
- AWS Config Rules for compliance
- ABAC (Attribute-Based Access Control)
- SCPs (Service Control Policies)

Features:
- Multi-account architecture
- Cost optimization patterns
- Security best practices
- Comprehensive documentation

Tech: Terraform, AWS Organizations, IAM Identity Center

terraform/modules/ram-share/README.md

@@ -0,0 +1,34 @@
+# ram-share
+
+Terraform module for AWS landing zone pattern.
+
+Share resources across accounts via AWS Resource Access Manager.
+
+## Planned Features
+
+- [ ] VPC subnet sharing
+- [ ] Transit Gateway sharing
+- [ ] Route53 Resolver rule sharing
+- [ ] Organization-wide sharing option
+- [ ] OU-level sharing
+
+## Planned Usage
+
+```hcl
+module "vpc_share" {
+  source = "../modules/ram-share"
+  
+  name = "shared-vpc-subnets"
+  
+  resources = [
+    aws_subnet.private_a.arn,
+    aws_subnet.private_b.arn,
+  ]
+  
+  # Share with specific accounts
+  principals = ["111111111111", "222222222222"]
+  
+  # Or share with entire org
+  # allow_organization = true
+}
+```