Gluetun: fix healthcheck (no curl in image; /health is not an endpoint)

The gluetun image ships wget, not curl, and its status server answers 200 at
/ on port 8000 (not /health). The old curl-based healthcheck always failed, so
the container read 'unhealthy' even with a working tunnel. Use wget against /.

dankclaw/compose.yaml

@@ -26,7 +26,9 @@ services:
       # SearXNG's published port lives on gluetun (network_mode: service:gluetun)
       - "8081:8080"
     healthcheck:
-      test: ["CMD", "curl", "-sf", "http://localhost:8000/health"]
+      # The gluetun image has no curl; its status server answers 200 at /
+      # on port 8000. Use wget (present in the image) against that path.
+      test: ["CMD", "wget", "-qO", "/dev/null", "http://localhost:8000/"]
       interval: 60s
       timeout: 10s
       retries: 3