Devices: fixes from review round 5

- A switch publishes the new headset at once, so the page clears the old one's
  panels and the lists behind them (games, store, Android apps, screenshots).
- The page names the headset its changes are for (X-Frame-Device); the server
  refuses one meant for a headset it has switched away from (409).
- A rejected address edit changes nothing.
- Test now goes to the IPv4 address that answered, like the connection.

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

ui/frame_devices.py

@@ -562,15 +562,20 @@ class Registry:
         with self.lock:
             d = self._find(device_id)
             a = self._addr(d, host)
-            if new_host is not None and new_host != host:
+            # Check everything first: a rejected edit changes nothing.
+            moved = new_host is not None and new_host != host
+            if moved:
                 new_host = check_host(new_host)
                 if any(x["host"] == new_host for x in d["addresses"]):
                     raise DeviceError(f"{new_host} is already on the list")
+            kind = None if kind is None else check_kind(kind)
+            label = None if label is None else check_text(label, "label")
+            if moved:
                 a.update(host=new_host, networks=[], last_ok=None, last_rtt_ms=None)  # a new place: learn again
             if kind is not None:
-                a["kind"] = check_kind(kind)
+                a["kind"] = kind
             if label is not None:
-                a["label"] = check_text(label, "label")
+                a["label"] = label
             self.save()
             return copy.deepcopy(a)