fix: hide synthetic rtt history keys from plugin accordion list

hbd/server/http.py

@@ -210,6 +210,16 @@ def _mask_config_for_api(config) -> dict:
     return result
 
 
+def _visible_plugin_names(plugin_data: dict) -> list:
+    """Plugin names to render as accordion sections.
+
+    Excludes synthetic rtt_ipv4 / rtt_ipv6 history streams (written by
+    udp.py for charting) which aren't real client plugins and have no
+    accordion renderer.
+    """
+    return [p for p in plugin_data.keys() if not p.startswith("rtt_")]
+
+
 def _build_host_info(host, threshold_checker=None) -> dict:
     """Assemble the info payload for GET /api/0/hosts/{hostname}/info."""
     hbc_version = None
@@ -767,7 +777,7 @@ async def start(
             if host.plugin_data:
                 hosts_with_plugins.append({
                     "name": hostname,
-                    "plugins": list(host.plugin_data.keys()),
+                    "plugins": _visible_plugin_names(host.plugin_data),
                     "is_owner": _can_own_host(current_user, host),
                     "owner": host.owner,
                 })