feat: add Terragrunt Apply workflow for CI/CD integration

Author: gcharest

.github/workflows/terragrunt-apply.yml

@@ -0,0 +1,73 @@
+name: Terragrunt Apply
+
+on:
+    push:
+        branches:
+            - main
+        paths:
+            - "terragrunt/**"
+            - ".github/workflows/terragrunt-apply.yml"
+    workflow_dispatch:
+
+permissions:
+    id-token: write
+    contents: read
+
+env:
+    AWS_REGION: us-east-1
+    TERRAFORM_VERSION: 1.14.5
+    TERRAGRUNT_VERSION: 0.99.4
+
+concurrency:
+    group: terragrunt-apply
+    cancel-in-progress: false
+
+jobs:
+    terragrunt-apply:
+        name: Terragrunt Apply
+        runs-on: ubuntu-latest
+        steps:
+            - name: Checkout code
+              uses: actions/checkout@v4
+
+            - name: Setup Terraform
+              uses: hashicorp/setup-terraform@v3
+              with:
+                  terraform_version: ${{ env.TERRAFORM_VERSION }}
+                  terraform_wrapper: false
+
+            - name: Setup Terragrunt
+              run: |
+                  wget -q https://github.com/gruntwork-io/terragrunt/releases/download/v${{ env.TERRAGRUNT_VERSION }}/terragrunt_linux_amd64
+                  chmod +x terragrunt_linux_amd64
+                  sudo mv terragrunt_linux_amd64 /usr/local/bin/terragrunt
+                  terragrunt --version
+
+            - name: Configure AWS credentials
+              uses: aws-actions/configure-aws-credentials@v4
+              with:
+                  role-to-assume: arn:aws:iam::${{ secrets.AWS_ACCOUNT_ID }}:role/github-actions-terragrunt-role
+                  aws-region: ${{ env.AWS_REGION }}
+                  role-session-name: github-terragrunt-apply
+
+            - name: Terragrunt Init All
+              working-directory: terragrunt/environments/prod
+              run: |
+                  terragrunt run --all init
+
+            - name: Terragrunt Apply All Modules
+              working-directory: terragrunt/environments/prod
+              run: |
+                  terragrunt run --all apply -auto-approve
+
+            - name: Output Route53 Nameservers
+              if: success()
+              working-directory: terragrunt/environments/prod/route53-zone
+              run: |
+                  echo "## ✅ Infrastructure Deployed Successfully" >> $GITHUB_STEP_SUMMARY
+                  echo "" >> $GITHUB_STEP_SUMMARY
+                  echo "**Update your domain registrar with these nameservers:**" >> $GITHUB_STEP_SUMMARY
+                  echo "" >> $GITHUB_STEP_SUMMARY
+                  echo "\`\`\`" >> $GITHUB_STEP_SUMMARY
+                  terragrunt output -raw nameservers_string >> $GITHUB_STEP_SUMMARY
+                  echo "\`\`\`" >> $GITHUB_STEP_SUMMARY