feat(world): port retail portal-space viewport

Replace the opaque teleport cover with the DAT-authored CreatureMode tunnel, exact retail camera/light/animation timing and easing, and animation-hook audio routing. Compose portal and fade passes below retained UI so gameplay windows and input remain active through F751 travel.

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

tests/AcDream.App.Tests/Rendering/PortalTunnelAssetTests.cs

@@ -0,0 +1,116 @@
+using AcDream.App.Rendering;
+using AcDream.App.UI;
+using AcDream.Content.Vfx;
+using AcDream.Core.World;
+using DatReaderWriter;
+using DatReaderWriter.DBObjs;
+using DatReaderWriter.Enums;
+using DatReaderWriter.Options;
+using Xunit.Sdk;
+
+namespace AcDream.App.Tests.Rendering;
+
+public sealed class PortalTunnelAssetTests
+{
+    [Fact]
+    public void InstalledDat_ResolvesRetailPortalSetupAndAnimation()
+    {
+        string? datDir = ResolveDatDir();
+        if (datDir is null)
+            throw SkipException.ForSkip(
+                "Installed client_portal.dat is required for the portal-space asset gate.");
+
+        using var dats = new DatCollection(datDir, DatAccessType.Read);
+        uint setupDid = RetailDataIdResolver.Resolve(
+            dats,
+            PortalTunnelPresentation.SetupClientEnum,
+            PortalTunnelPresentation.ClientEnumCategory);
+        uint animationDid = RetailDataIdResolver.Resolve(
+            dats,
+            PortalTunnelPresentation.AnimationClientEnum,
+            PortalTunnelPresentation.ClientEnumCategory);
+
+        Assert.NotEqual(0u, setupDid);
+        Assert.NotEqual(0u, animationDid);
+        Assert.Equal(0x02000306u, setupDid);
+        Assert.Equal(0x030005ACu, animationDid);
+        Setup setup = Assert.IsType<Setup>(dats.Get<Setup>(setupDid));
+        Animation animation = Assert.IsType<Animation>(
+            new RetailAnimationLoader(dats).LoadAnimation(animationDid));
+
+        Assert.NotEmpty(setup.Parts);
+        Assert.True(
+            animation.PartFrames.Count >= TeleportAnimSequencer.TunnelEndFrame,
+            $"Retail tunnel timing samples frame {TeleportAnimSequencer.TunnelEndFrame}, "
+            + $"but animation 0x{animationDid:X8} has only {animation.PartFrames.Count} frames.");
+        Assert.All(
+            setup.Parts,
+            part => Assert.Equal(0x01u, ((uint)part >> 24) & 0xFFu));
+        Assert.Equal(0u, (uint)setup.DefaultAnimation);
+        Assert.Equal(0u, (uint)setup.DefaultScript);
+        Assert.Equal(0u, (uint)setup.DefaultScriptTable);
+        var hook = Assert.Single(animation.PartFrames.SelectMany(frame => frame.Hooks));
+        Assert.Equal(DatReaderWriter.Enums.AnimationHookType.SoundTweaked, hook.HookType);
+    }
+
+    [Fact]
+    public void PortalTunnelCamera_UsesRetailEyeAndRotatesAroundAcUpAxis()
+    {
+        var camera = new PortalTunnelCamera
+        {
+            DirectionDegrees = 0f,
+            Aspect = 1f,
+        };
+        Assert.True(System.Numerics.Matrix4x4.Invert(camera.View, out var world));
+        Assert.Equal(PortalTunnelCamera.RetailEye.X, world.Translation.X, precision: 5);
+        Assert.Equal(PortalTunnelCamera.RetailEye.Y, world.Translation.Y, precision: 5);
+        Assert.Equal(PortalTunnelCamera.RetailEye.Z, world.Translation.Z, precision: 5);
+
+        camera.DirectionDegrees = 90f;
+        Assert.True(System.Numerics.Matrix4x4.Invert(camera.View, out var rotatedWorld));
+        System.Numerics.Vector3 up = System.Numerics.Vector3.Normalize(
+            System.Numerics.Vector3.TransformNormal(System.Numerics.Vector3.UnitY, rotatedWorld));
+        Assert.Equal(0f, up.X, precision: 5);
+        Assert.Equal(0f, up.Y, precision: 5);
+        Assert.Equal(1f, up.Z, precision: 5);
+    }
+
+    [Theory]
+    [InlineData(45f)]
+    [InlineData(60f)]
+    [InlineData(90f)]
+    public void PortalTunnelCamera_UsesActiveSmartBoxFieldOfView(float degrees)
+    {
+        float expected = degrees * (MathF.PI / 180f);
+        var smartBoxProjection = System.Numerics.Matrix4x4.CreatePerspectiveFieldOfView(
+            expected,
+            16f / 9f,
+            0.1f,
+            5000f);
+        var camera = new PortalTunnelCamera();
+
+        camera.UseSmartBoxFov(smartBoxProjection);
+
+        Assert.Equal(expected, camera.FovRadians, precision: 5);
+    }
+
+    private static string? ResolveDatDir()
+    {
+        string? configured = System.Environment.GetEnvironmentVariable("ACDREAM_DAT_DIR");
+        if (!string.IsNullOrWhiteSpace(configured)
+            && File.Exists(Path.Combine(configured, "client_portal.dat")))
+            return configured;
+
+        const string installed = @"C:\Turbine\Asheron's Call";
+        if (File.Exists(Path.Combine(installed, "client_portal.dat")))
+            return installed;
+
+        string conventional = Path.Combine(
+            System.Environment.GetFolderPath(System.Environment.SpecialFolder.UserProfile),
+            "Documents",
+            "Asheron's Call");
+        return File.Exists(Path.Combine(conventional, "client_portal.dat"))
+            ? conventional
+            : null;
+    }
+}