feat(runtime): define borrowed views commands and ordered events

Establish the J1 presentation-independent contract with instance-scoped clocks and generations, immutable borrowed views, typed generation-gated commands, normalized ordered diagnostics, and teardown acknowledgements. Route graphical startup plus press-time selection, movement, and combat through focused App adapters over the exact existing owners without adding a queue or mirrored world.

Validated by the Release solution build, 13 Runtime tests, 3,838 App tests with three existing skips, and the complete 8,424-test Release suite with five existing skips.

Co-authored-by: Codex <codex@openai.com>

tests/AcDream.Runtime.Tests/GameRuntimeContractTests.cs

@@ -0,0 +1,125 @@
+namespace AcDream.Runtime.Tests;
+
+public sealed class GameRuntimeContractTests
+{
+    [Fact]
+    public void InstanceClock_NormalizesHostTimeAndCanFreezeSimulation()
+    {
+        var first = new GameRuntimeClock();
+        var second = new GameRuntimeClock();
+
+        RuntimeFrameTime frame1 = first.Advance(0.25);
+        RuntimeFrameTime frozen = first.Advance(0.5, advanceSimulationTime: false);
+        RuntimeFrameTime invalid = first.Advance(double.NaN);
+
+        Assert.Equal(1UL, frame1.FrameNumber);
+        Assert.Equal(0.25, frame1.DeltaSeconds);
+        Assert.Equal(0.25, frame1.SimulationTimeSeconds);
+        Assert.Equal(2UL, frozen.FrameNumber);
+        Assert.Equal(0.5, frozen.DeltaSeconds);
+        Assert.Equal(0.25, frozen.SimulationTimeSeconds);
+        Assert.Equal(3UL, invalid.FrameNumber);
+        Assert.Equal(0.0, invalid.DeltaSeconds);
+        Assert.Equal(0.25, invalid.SimulationTimeSeconds);
+        Assert.Equal(0UL, second.FrameNumber);
+        Assert.Equal(0.0, second.SimulationTimeSeconds);
+    }
+
+    [Theory]
+    [InlineData(double.NegativeInfinity)]
+    [InlineData(double.PositiveInfinity)]
+    [InlineData(double.NaN)]
+    [InlineData(-1.0)]
+    [InlineData(0.0)]
+    public void InstanceClock_InvalidDeltaNormalizesToZero(double input)
+    {
+        Assert.Equal(0.0, GameRuntimeClock.NormalizeDeltaSeconds(input));
+    }
+
+    [Fact]
+    public void GenerationAndTeardownAcknowledgementAreExact()
+    {
+        RuntimeGenerationToken first = RuntimeGenerationToken.Initial.Next();
+        var complete = new RuntimeTeardownAcknowledgement(
+            first,
+            first.Next(),
+            RuntimeCommandStatus.Accepted,
+            RuntimeTeardownStage.Complete);
+        var stale = complete with
+        {
+            Status = RuntimeCommandStatus.StaleGeneration,
+        };
+        var partial = complete with
+        {
+            CompletedStages =
+                RuntimeTeardownStage.CommandsInert
+                | RuntimeTeardownStage.InboundDetached,
+        };
+
+        Assert.Equal(1UL, first.Value);
+        Assert.True(complete.IsComplete);
+        Assert.False(stale.IsComplete);
+        Assert.False(partial.IsComplete);
+    }
+
+    [Fact]
+    public void EventSequencersAreMonotonicAndInstanceScoped()
+    {
+        var first = new RuntimeEventSequencer();
+        var second = new RuntimeEventSequencer();
+        var generation = new RuntimeGenerationToken(7);
+
+        RuntimeEventStamp one = first.Next(generation, frameNumber: 11);
+        RuntimeEventStamp two = first.Next(generation, frameNumber: 12);
+        RuntimeEventStamp independent = second.Next(generation, frameNumber: 99);
+
+        Assert.Equal(1UL, one.Sequence);
+        Assert.Equal(2UL, two.Sequence);
+        Assert.Equal(1UL, independent.Sequence);
+        Assert.Equal(12UL, two.FrameNumber);
+        Assert.Equal(99UL, independent.FrameNumber);
+    }
+
+    [Fact]
+    public void TraceRecorderNormalizesTypedDeltasWithoutRetainingOwners()
+    {
+        var recorder = new RuntimeTraceRecorder();
+        var stamp = new RuntimeEventStamp(
+            new RuntimeGenerationToken(3),
+            Sequence: 1,
+            FrameNumber: 8);
+        var command = new RuntimeCommandDelta(
+            stamp,
+            RuntimeCommandDomain.Selection,
+            (int)RuntimeSelectionCommand.SelectClosestHostile,
+            RuntimeCommandStatus.Accepted,
+            PrimaryObjectId: 0x50000001u);
+        var chat = new RuntimeChatDelta(
+            stamp with { Sequence = 2 },
+            new RuntimeChatEntry(
+                Revision: 4,
+                SenderGuid: 0x50000002u,
+                Kind: 2,
+                Sender: "Grey",
+                Text: "hello",
+                ChannelName: "General"));
+
+        recorder.OnCommand(in command);
+        recorder.OnChat(in chat);
+
+        Assert.Collection(
+            recorder.Entries,
+            entry =>
+            {
+                Assert.Equal(RuntimeTraceKind.Command, entry.Kind);
+                Assert.Equal(0x50000001u, entry.PrimaryObjectId);
+                Assert.Equal((long)RuntimeCommandStatus.Accepted, entry.Value);
+            },
+            entry =>
+            {
+                Assert.Equal(RuntimeTraceKind.Chat, entry.Kind);
+                Assert.Equal(4L, entry.Value);
+                Assert.Equal("General|Grey|hello", entry.Text);
+            });
+    }
+}