feat: Add Packer build automation scripts

- Added packer/variables.pkr.hcl with configurable variables
- Added build-template.sh with interactive build script
- Added .env.example for environment configuration
- Updated windows.pkr.hcl to use variables
- Supports environment variables and command line arguments

.env.example

@@ -0,0 +1,19 @@
+# Windows Automation Environment Configuration
+# Copy this file to .env and fill in your values
+
+# Proxmox Configuration
+export PROXMOX_URL="https://la-vmh-07:8006/api2/json"
+export PROXMOX_USERNAME="root@pam"
+export PROXMOX_PASSWORD="your-proxmox-root-password"
+export PROXMOX_NODE="la-vmh-07"
+
+# Windows Configuration
+export WINRM_PASSWORD="PackerPassword123!"
+
+# Proxmox API Token (alternative to password)
+export PM_API_TOKEN_ID="root@pam!forgejo-automation"
+export PM_API_TOKEN_SECRET="your-api-token-secret"
+
+# Terraform Variables
+export TF_VAR_build_id="001"
+export TF_VAR_template_vm_id="9000"