feat(mosstank): add VTank-style automation PoC

tests/AcDream.Core.Tests/Plugins/PluginCommandRegistryTests.cs

@@ -0,0 +1,59 @@
+using AcDream.Core.Plugins;
+using AcDream.Plugin.Abstractions;
+
+namespace AcDream.Core.Tests.Plugins;
+
+public sealed class PluginCommandRegistryTests
+{
+    [Fact]
+    public void RegisteredVerbHandlesBothPrefixesCaseInsensitively()
+    {
+        var registry = new PluginCommandRegistry();
+        var seen = new List<PluginCommand>();
+        using IDisposable lease = registry.Register("vt", seen.Add);
+
+        Assert.True(registry.TryHandle("/VT start"));
+        Assert.True(registry.TryHandle(" @vt   opt get EnableCombat "));
+        Assert.Equal(2, seen.Count);
+        Assert.Equal("start", seen[0].Arguments);
+        Assert.Equal("opt get EnableCombat", seen[1].Arguments);
+        Assert.Equal("/VT start", seen[0].RawText);
+    }
+
+    [Fact]
+    public void ExactLeaseRemovalDoesNotConsumeUnknownServerCommand()
+    {
+        var registry = new PluginCommandRegistry();
+        IDisposable lease = registry.Register("vt", static _ => { });
+        lease.Dispose();
+
+        Assert.False(registry.TryHandle("/vt start"));
+        Assert.False(registry.TryHandle("hello"));
+    }
+
+    [Fact]
+    public void DuplicateVerbIsRejectedWithoutReplacingOwner()
+    {
+        var registry = new PluginCommandRegistry();
+        int calls = 0;
+        using IDisposable lease = registry.Register("vt", _ => calls++);
+
+        Assert.Throws<InvalidOperationException>(() =>
+            registry.Register("VT", static _ => { }));
+        Assert.True(registry.TryHandle("/vt"));
+        Assert.Equal(1, calls);
+    }
+
+    [Fact]
+    public void HandlerFailureIsContainedAndReported()
+    {
+        Exception? failure = null;
+        var registry = new PluginCommandRegistry((_, error) => failure = error);
+        using IDisposable lease = registry.Register(
+            "vt",
+            static _ => throw new InvalidOperationException("broken"));
+
+        Assert.True(registry.TryHandle("/vt start"));
+        Assert.Equal("broken", failure?.Message);
+    }
+}