test: add remote runner vagrant scenario

readme.md

@@ -12,6 +12,10 @@ flows.
   target HTTP service, runs `uptimerunner` once, verifies the runner fetches
   assigned checks, executes them from the local machine, and reports results
   back.
+- `uptimerunner-vagrant`: starts controller and runner VMs with Vagrant,
+  installs `uptimerunner` as a systemd service in the runner VM, and verifies
+  that the remote runner executes a runner-local HTTP check and submits the
+  result to the controller VM.
 
 ## Run
 
@@ -19,3 +23,21 @@ flows.
 pnpm bootstrap:components
 pnpm test
 ```
+
+Run the remote-runner VM scenario with:
+
+```bash
+pnpm scenario:uptimerunner-vagrant
+```
+
+The VM scenario defaults to the `libvirt` Vagrant provider. Override it with
+`UPTIMELINK_VAGRANT_PROVIDER=virtualbox` if needed.
+
+If the current shell has not picked up newly added `libvirt` group membership,
+run it without restarting the machine using:
+
+```bash
+sg libvirt -c 'pnpm scenario:uptimerunner-vagrant'
+```
+
+Stop or remove the VMs with `pnpm vagrant:halt` or `pnpm vagrant:destroy`.