Refactor CI/CD workflow to utilize NixOS VM for testing

- Changed the CI workflow to run tests inside a NixOS virtual machine instead of directly on the runner.
- Updated the NixOS VM configuration to include necessary dependencies and services for testing.
- Added a script to handle test execution within the VM, including setup for Python and Node.js environments.
- Implemented SSH access to the VM for remote operations and streamlined the process of starting and stopping the VM during tests.
- Enhanced the workflow to build the VM and copy the codebase for testing, ensuring a more isolated and consistent testing environment.

nix/vm-config.nix

@@ -0,0 +1,9 @@
+# VM configuration entry point for CI/CD
+{ pkgs, lib, ... }:
+
+{
+  imports = [
+    ./test-vm.nix
+  ];
+}
+