fix: use the latest RTT sample, not the oldest, in host info API

hbd/server/http.py

@@ -275,7 +275,7 @@ def _build_host_info(host, threshold_checker=None) -> dict:
             "family": getattr(conn, "afam", family),
             "addr": getattr(conn, "addr", ""),
             "state": getattr(conn, "state", ""),
-            "rtt": (getattr(conn, "rtts", None) or [None])[0],
+            "rtt": (getattr(conn, "rtts", None) or [None])[-1],
             "statetime": getattr(conn, "statetime", None),
             "lastbeat": getattr(conn, "lastbeat", None),
         }

tests/test_http_host_info.py

@@ -1,5 +1,4 @@
 """Tests for _build_host_info helper in http.py."""
-import pytest
 from unittest.mock import MagicMock
 from hbd.server.http import _build_host_info
 
@@ -175,11 +174,11 @@ def test_build_host_info_covers_empty_when_exact_matches_only():
 
 
 class _FakeConnFull:
-    def __init__(self, afam, addr, state, rtt, statetime, lastbeat):
+    def __init__(self, afam, addr, state, rtt, statetime, lastbeat, rtts=None):
         self.afam = afam
         self.addr = addr
         self.state = state
-        self.rtts = [rtt]
+        self.rtts = rtts if rtts is not None else [rtt]
         self.statetime = statetime
         self.lastbeat = lastbeat
 
@@ -200,3 +199,14 @@ def test_build_host_info_connections_empty():
     host = _FakeHost()
     result = _build_host_info(host)
     assert result["connections"] == []
+
+
+def test_build_host_info_connection_rtt_uses_latest_sample():
+    """rtt should reflect the most recent sample, not the oldest retained one."""
+    host = _FakeHost(connections={
+        "IPv4": _FakeConnFull("IPv4", "10.0.0.5", "up", None, 1000.0, 2000.0,
+                              rtts=[100.0, 50.0, 14.2]),
+    })
+    result = _build_host_info(host)
+    conns = {c["family"]: c for c in result["connections"]}
+    assert conns["IPv4"]["rtt"] == 14.2