feat: SSH card UX, agent version sync, persistent ssh_admin_ok (0.11.5)

Silent SSH probe on host card open; manual test feedback auto-hides. Persist ssh_admin_ok in DB (migration 019). After agent update read version from host and refresh UI.

backend/tests/test_linux_admin_settings.py

@@ -116,6 +116,11 @@ def test_host_ssh_test_success(jwt_headers, client, db_session, monkeypatch):
     assert body["ok"] is True
     assert "hostname=ubabuba" in body["message"]
     assert body["target"] == "ubabuba"
+    assert body["ssh_admin_ok"] is True
+
+    db_session.refresh(host)
+    assert host.ssh_admin_ok is True
+    assert host.ssh_admin_checked_at is not None
 
 
 def test_host_agent_update_success(jwt_headers, client, db_session, monkeypatch):
@@ -149,3 +154,5 @@ def test_host_agent_update_success(jwt_headers, client, db_session, monkeypatch)
     body = response.json()
     assert body["ok"] is True
     assert body["target"] == "ubabuba"
+    if "product_version" in body:
+        assert body["product_version"] is None or isinstance(body["product_version"], str)