feat(monitors): a DNS monitor can name a resolver; the host page puts Ansible above Docker (#5214)

DNS monitors take an optional Resolver, a server's IP. Set, the check asks
that server directly for A and AAAA over UDP and records how long it took
to answer; empty keeps today's lookup through the container's resolver.
"Does my local DNS still answer for public names" and "does 1.1.1.1" are
now separate monitors. No new dependency.

On a host's page the Ansible card moves above the Docker list, which can
run to dozens of containers and hid it.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/core/test_host_page.py

@@ -0,0 +1,19 @@
+"""The host page: what sits where (#5214)."""
+from types import SimpleNamespace
+
+from quart import render_template, session
+
+
+async def test_ansible_comes_before_the_docker_list(app, monkeypatch):
+    # The Docker list can run to dozens of containers; Ansible under it was
+    # easy to miss, so it sits above.
+    monkeypatch.setitem(app.config, "PLUGINS", {"docker": {"enabled": True}})
+    host = SimpleNamespace(id="h1", name="box", address="10.0.0.5")
+    async with app.test_request_context("/hosts/h1"):
+        session["user_role"] = "operator"
+        page = await render_template(
+            "hosts/detail.html", host=host, monitors=[], uptime=None, alerts=[],
+            monitor_types=[], linked_target=None, linkable_targets=[], ansible_sources=[])
+    docker = page.index('hx-get="/plugins/docker/host/h1"')
+    assert page.index(">Ansible</h3>") < docker
+    assert page.index('hx-get="/plugins/host_agent/panel/h1"') < docker