Launcher milestone 2: player list, kick/ban, live stats

Adds an admin-protocol client (token-authed TCP JSON on 127.0.0.1:AdminPort,
reusing the server's .admin-token) that polls connected players and status
every 3s, plus Kick/Ban on the selected player and a players/uptime readout.

host/ViewModels/PlayerRow.cs

@@ -0,0 +1,13 @@
+namespace CommonwealthOnline.Host.ViewModels;
+
+public sealed class PlayerRow
+{
+    public uint PlayerId { get; init; }
+    public string Label { get; init; } = string.Empty;
+    public string Address { get; init; } = string.Empty;
+    public long PacketsReceived { get; init; }
+    public long PacketsSent { get; init; }
+
+    public string Display =>
+        $"#{PlayerId}   {(string.IsNullOrEmpty(Label) ? "player" : Label)}   {Address}   ↓{PacketsReceived} ↑{PacketsSent}";
+}