verify-vm: fix Vagrantfile for first real run

Two issues surfaced during the first end-to-end verification attempt
(verify.sh pwnkit, generic/ubuntu2004):

1. 'The machine with the name skk-pwnkit was not found' — the original
   Vagrantfile used c.vm.box/hostname without a c.vm.define block, so
   passing a machine name to 'vagrant up <name>' had nothing to match.
   Wrap every per-machine config in 'c.vm.define host do |m| ... end'
   so each module gets its own tracked machine in
   .vagrant/machines/skk-<module>/parallels/.

2. 'Installing the proper version of Parallels Tools' fails on
   Ubuntu 20.04: 'Error: current Linux kernel version 5.4.0-169-generic
   is outdated and not supported'. The latest Parallels Tools wants
   newer guest kernels. We don't need the Tools at all — rsync
   sync_folder over plain SSH does our source mount. Disable both:
     p.update_guest_tools = false
     p.check_guest_tools  = false

Verified externally (with Apple hypervisor as a temporary bypass
during the user's pending Parallels-extension allow + Mac restart):
the VM boots, SSH connects, network works. The only remaining gate
was the Parallels Tools provisioner now skipped.

tools/verify-vm/Vagrantfile

@@ -24,22 +24,30 @@ kver    = ENV["SKK_VM_KERNEL_VERSION"] || ""
 host    = ENV["SKK_VM_HOSTNAME"]       || "skk-verify"
 
 Vagrant.configure("2") do |c|
-  c.vm.box = box
-  c.vm.hostname = host
+  # Define ONE Vagrant machine named after SKK_VM_HOSTNAME. Per-module
+  # isolation: each module gets its own `skk-<module>` machine that
+  # vagrant tracks in .vagrant/machines/skk-<module>/parallels/.
+  c.vm.define host do |m|
+    m.vm.box = box
+    m.vm.hostname = host
 
-  c.vm.synced_folder REPO_ROOT, "/vagrant",
+    m.vm.synced_folder REPO_ROOT, "/vagrant",
       type: "rsync", rsync__exclude: ["build/", ".git/", "*.o", "skeletonkey-test*"]
 
-  c.vm.provider "parallels" do |p|
+    m.vm.provider "parallels" do |p|
       p.memory = 2048
       p.cpus   = 2
       p.name   = host
-    # Headless: don't pop a Parallels GUI window for every verify run.
-    p.update_guest_tools = true
+      # Don't auto-update Parallels Tools: the installer fails on older
+      # guest kernels (e.g. Ubuntu 20.04's 5.4.0-169 is "outdated and
+      # not supported" by latest tools). We use rsync over SSH for
+      # sync_folder, which doesn't need the guest tools at all.
+      p.update_guest_tools = false
+      p.check_guest_tools  = false
     end
 
     # 1. Always install build deps + sudo (needed for module verification).
-  c.vm.provision "shell", inline: <<-SHELL
+    m.vm.provision "shell", inline: <<-SHELL
       set -e
       if command -v apt-get >/dev/null 2>&1; then
           export DEBIAN_FRONTEND=noninteractive
@@ -52,7 +60,7 @@ Vagrant.configure("2") do |c|
 
     # 2. Pin target kernel if requested. Reboot needed afterward.
     if !pkg.empty?
-    c.vm.provision "shell", name: "pin-kernel-#{pkg}", inline: <<-SHELL
+      m.vm.provision "shell", name: "pin-kernel-#{pkg}", inline: <<-SHELL
         set -e
         if dpkg-query -W -f='${Status}' #{pkg} 2>/dev/null | grep -q 'install ok installed'; then
             echo "[=] #{pkg} already installed"
@@ -72,9 +80,11 @@ Vagrant.configure("2") do |c|
     end
 
     # 3. Build SKELETONKEY in-VM and run --explain --active for the target module.
-  #    SKK_MODULE is set by verify.sh on the second-pass `vagrant provision` call
-  #    (post-reboot if kernel was pinned).
-  c.vm.provision "shell", name: "build-and-verify", run: "never", inline: <<-SHELL
+    #    SKK_MODULE is set by verify.sh on the second-pass `vagrant provision`
+    #    call (post-reboot if kernel was pinned).
+    m.vm.provision "shell", name: "build-and-verify", run: "never",
+      env: { "SKK_MODULE" => ENV["SKK_MODULE"] || "" },
+      inline: <<-SHELL
       set -e
       cd /vagrant
       echo "[*] kernel: $(uname -r)"
@@ -86,4 +96,5 @@ Vagrant.configure("2") do |c|
       echo
       ./skeletonkey --explain "${SKK_MODULE}" --active 2>&1 || true
     SHELL
+  end
 end