feat: add CI workflow and integration test stub

tests/run-integration.sh

@@ -0,0 +1,28 @@
+#!/usr/bin/env bash
+# Integration test suite for PR validation on staging VM
+#
+# This script runs inside the staging VM after the PR's NixOS config
+# has been deployed. It tests that all services come up correctly.
+#
+# Usage: pr-test-vm ssh < tests/run-integration.sh
+
+set -euo pipefail
+
+echo "==> Integration tests starting..."
+
+# Test Docker is running
+echo "  [1/3] Docker daemon..."
+docker info > /dev/null 2>&1 || { echo "FAIL: Docker not running"; exit 1; }
+echo "       OK"
+
+# Test compose stack can start
+echo "  [2/3] Docker Compose stack..."
+docker compose -f /opt/data/compose.yml ps > /dev/null 2>&1 || { echo "FAIL: Compose stack not running"; exit 1; }
+echo "       OK"
+
+# Test services are healthy
+echo "  [3/3] Service health checks..."
+# TODO: add per-service health checks
+echo "       OK (placeholder)"
+
+echo "==> All integration tests passed."