terraform: add parameterized multi-VM deployment system

Implements Phase 1 of the OpenTofu deployment plan:
- Replace single-VM configuration with locals-based for_each pattern
- Support multiple VMs in single deployment
- Automatic DHCP vs static IP detection
- Configurable defaults with per-VM overrides
- Dynamic outputs for VM IPs and specifications

New files:
- outputs.tf: Dynamic outputs for deployed VMs
- vms.tf: VM definitions using locals.vms map

Updated files:
- variables.tf: Added default variables for VM configuration
- README.md: Comprehensive documentation and examples

Removed files:
- vm.tf: Replaced by new vms.tf (archived as vm.tf.old, then removed)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

terraform/outputs.tf

@@ -0,0 +1,24 @@
+# Dynamic outputs for all deployed VMs
+
+output "vm_ips" {
+  description = "IP addresses and SSH commands for deployed VMs"
+  value = {
+    for name, vm in proxmox_vm_qemu.vm : name => {
+      ip          = vm.default_ipv4_address
+      ssh_command = "ssh root@${vm.default_ipv4_address}"
+    }
+  }
+}
+
+output "deployment_summary" {
+  description = "Summary of deployed VMs with their specifications"
+  value = {
+    for name, vm in proxmox_vm_qemu.vm : name => {
+      cpu_cores = vm.cpu[0].cores
+      memory_mb = vm.memory
+      disk_size = vm.disks[0].virtio[0].virtio0[0].disk[0].size
+      ip        = vm.default_ipv4_address
+      node      = vm.target_node
+    }
+  }
+}