feat(railiance): implement CUST-WP-0032 Haskell build machine infra

Packer build definition, cloud-init autoinstall, GHCup toolchain script,
boot-time registration agent (state-hub + autossh dual tunnel), systemd
unit, key injection, remote-build Makefile, smoke test, and deployment
README. All 15 tasks complete.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

infra/build-machines/haskell/scripts/setup-vm.sh

@@ -0,0 +1,13 @@
+#!/bin/bash
+# setup-vm.sh — switches imported VM from NAT to bridged networking
+VM_NAME="${1:?Usage: setup-vm.sh <vm-name> [adapter]}"
+# Auto-detect first available bridge interface if not specified
+ADAPTER="${2:-$(VBoxManage list bridgedifs | awk '/^Name:/{print $2; exit}')}"
+
+VBoxManage modifyvm "$VM_NAME" \
+  --nic1 bridged \
+  --bridgeadapter1 "$ADAPTER" \
+  --memory 8192 --cpus 4
+
+echo "Configured $VM_NAME: bridged on $ADAPTER"
+echo "Next: inject keys with scripts/inject-keys.sh, then start VM"