RioSerialLink: type-aware resolution closes the straggler-reply hole

Bench round 3 (testlogs/riomash-patched-62500-sw): lamp glitches
persisted because reply-resolution was type-blind — an analog reply
still crossing USB from the previous poll could falsely confirm the
NEXT command (usually a lamp write) before the board judged it. Now a
reply resolves only its MATCHING pending request (analog/version/
check); ACK/NAK stay type-blind, which is safe because the board's TX
ISR prioritizes ACK/NAK ahead of reply data, so a command's ACK cannot
trail into its successor's window. Budget-exhausted drops settle 10ms
before releasing the gate so late stragglers land on an empty pending.

New test: a stray AnalogReply must not resolve a pending lamp command.
283 green; selftest regression unchanged.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

tests/RioJoy.Core.Tests/Serial/RioSerialLinkTests.cs

@@ -276,6 +276,33 @@ public class RioSerialLinkTests
         await run;
     }
 
+    [Fact]
+    public async Task AnalogReply_DoesNotResolve_PendingLampCommand()
+    {
+        var fake = new FakeTransport();
+        var link = new RioSerialLink(fake, StopAndWait(limit: 1, timeoutMs: 250));
+
+        using var cts = new CancellationTokenSource();
+        Task run = link.RunAsync(cts.Token);
+
+        // Lamp command in flight; a straggler analog reply (from an earlier
+        // poll) arrives. It must NOT confirm the lamp — the lamp keeps waiting
+        // and is resolved only by its own ACK.
+        Task send = link.SendAsync(PacketBuilder.LampRequest(0x05, 0x02));
+        await fake.NextWriteAsync();
+        fake.Enqueue(PacketBuilder.Build(RioCommand.AnalogReply, new byte[10]));
+
+        await Task.Delay(100);
+        Assert.False(send.IsCompleted, "stray analog reply must not resolve a lamp command");
+
+        fake.Enqueue((byte)RioControl.Ack);
+        await send.WaitAsync(Timeout);
+        Assert.Equal(0, link.Retransmits);
+
+        cts.Cancel();
+        await run;
+    }
+
     [Fact]
     public async Task UnsolicitedNak_WithNothingPending_IsIgnored()
     {