Add Terragrunt installation to Dockerfile

Author: whiterabbit7516

images/devenv-main-arm64/.devcontainer/Dockerfile

@@ -193,7 +193,14 @@ RUN apt install -y 1password-cli \
 
 # terraform
 RUN apt-get install -y -q terraform \
-    && terraform version
+    && terraform version;
+
+# terragrunt
+RUN iwr https://github.com/gruntwork-io/terragrunt/releases/download/alpha-2026031001/terragrunt_linux_arm64.tar.gz -outfile terragrunt.tar.gz \
+    && tar xzf terragrunt.tar.gz \
+    && chmod +x ./terragrunt_linux_arm64 \
+    && mv ./terragrunt_linux_arm64 /usr/local/bin/terragrunt \
+    && terragrunt --version;
 
 # vault
 RUN apt-get install -y -q vault \