feat(quic): replace probe UDP data plane with QUIC datagrams

backend/tests/MoShiro.Backend.Tests/AgentHarness.cs

@@ -58,7 +58,7 @@ public sealed class AgentHarness : IAsyncDisposable
         var config = new AgentConfig
         {
             Fleet = { Server = backend.BaseAddress.ToString(), IdentityDir = directory },
-            Listen = { Bind = "127.0.0.1", ControlPort = 0, UdpPorts = [0], TcpPorts = [0] },
+            Listen = { Bind = "127.0.0.1", ControlPort = 0, QuicPorts = [0], TcpPorts = [0] },
         };
         configure?.Invoke(config);
         LoadedNodeIdentity identity = LoadedNodeIdentity.Load(directory);
@@ -87,7 +87,7 @@ public sealed class AgentHarness : IAsyncDisposable
     public async Task<ProbeSimulator> ConnectProbeAsync()
     {
         ProbeSimulator probe = await CreateProbeAsync();
-        await probe.ConnectAsync("127.0.0.1", App.ControlPort, TlsPublicKey, App.UdpPorts[0], NodeId);
+        await probe.ConnectAsync("127.0.0.1", App.ControlPort, TlsPublicKey, App.QuicPorts[0], NodeId);
         return probe;
     }
 
@@ -104,7 +104,7 @@ public sealed class AgentHarness : IAsyncDisposable
             }
 
             string kind = task["kind"]!.GetValue<string>();
-            var parameters = new JsonObject { ["port"] = kind == "udp_echo" ? App.UdpPorts[0] : App.TcpPorts[0] };
+            var parameters = new JsonObject { ["port"] = kind == "udp_echo" ? App.QuicPorts[0] : App.TcpPorts[0] };
             // 默认的 connect 模板在这些用例里不需要（也占预算）：对这个 Agent 关掉它
             bool enabled = kind != "connect";
             if (rateHz is { } hz && kind != "connect")