feat(render): Vulkan campaign V11 step 2 — delete the OpenGL backend

Vulkan is the sole, user-signed-off backend (V10 landed) and step 1
already removed ImGui/Studio/DevTools. This step deletes the GL
rendering backend itself: every Gpu/Gl/** implementation, the Wb
ManagedGL*/GLHelpers/GLSLShader/GLStateScope/RenderStateCache/
BindlessSupport family, Shader/ShaderProgramConstruction/SamplerCache,
RenderBootstrap, and RenderFrameGlStateController.

GameWindow.cs's Run()/CreateGraphics()/CreateBackbufferReader()/
OnLoad() collapse to their Vulkan-only arm; GameWindowGraphics loses
its OpenGlGameWindowGraphics subclass. RuntimeOptions.RenderBackend and
RenderBackendKind (incl. the Gl member of GpuBackendKind) are gone —
there is nothing left to select between. The five world-draw dual-arm
renderers (WbDrawDispatcher, EnvCellRenderer, TerrainModernRenderer,
ParticleRenderer, SkyRenderer) and the composition roots
(WorldRenderComposition, HostInputCameraComposition,
LivePresentationComposition, FrameRootComposition) collapse to their
RHI-only arm. GL-only diagnostic properties with a live external reader
(DynamicBufferCount and friends) simplify to a documented `=> 0`/no-op
rather than disappearing, since the reader is out of this commit's
scope.

A few GL-flavored mechanisms turned out to be backend-neutral once
isolated: GlConstructionCleanupLedger is renamed
ResourceConstructionCleanupLedger (exception-chain walking has nothing
to do with GL), and GlfwNativePlatformProbe moved out of the otherwise
GL-only GraphicalCapabilityRecord.cs into
GraphicalWindowBackendSelection.cs before the rest of that file was
deleted.

Test files with no surviving subject are deleted outright
(GraphicalCapabilityRequirementsTests, ShaderProgramConstructionTests,
PortalDepthShaderParityTests, TextureCacheBindlessTests,
TextRendererFailureSafetyTests, ClipFrameUploadTests, every
Gpu/Gl/*Tests, GlTextureOwnershipTests, RenderFrameGlStateControllerTests);
others get their dead GL-only members trimmed while their live
assertions stay (ClipFrameLayoutTests' MeshClipSsboBinding check now
reads GpuBindingModel.StorageClipRegions, the same binding index under
its new backend-neutral name; GpuResourceRetirementTransactionTests
drops its OpenGLGraphicsDevice-subclassing test double and the two GL
queue tests it existed for). EnvCellRendererTests' construction helper
now builds a real ObjectMeshManager via VulkanMeshPipelineDevice
instead of passing null through a null-forgiving operator, since the
RHI constructor never tolerated a null mesh manager and the old GL
constructor (which did) is gone.

Deferred to the next two steps, deliberately not touched here: the
Silk.NET.OpenGL/.Extensions.ARB package references, IMeshPipelineDevice.Gl
(WbMeshAdapter's GL? threading stays in place), Chorizite.Core's stale
csproj comment (the package itself is still load-bearing —
TextureFormat and friends are used well beyond the deleted
ManagedGLUniformBuffer), and the CI/gate scripts.

Build: `dotnet build AcDream.slnx -c Release` — 0 warnings, 0 errors.
Tests: full-solution `dotnet test` green across every project
(App.Tests 3937/3940 + 3 skips, Core.Tests 3296/3298 + 2 skips, all
others 100%); the 2 App.Tests names that flake under full-suite
parallel execution (#250-family, documented pre-existing) pass in
isolation.

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

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

@@ -58,8 +58,8 @@ public sealed class ResourceCleanupGroupTests
                 throw new InvalidOperationException("release failed");
         });
 
-        GlResourceConstructionException failure =
-            Assert.Throws<GlResourceConstructionException>(() =>
+        ResourceConstructionException failure =
+            Assert.Throws<ResourceConstructionException>(() =>
                 resources.RollbackConstructionAndThrow(
                     "construction failed",
                     new InvalidOperationException("original failure")));
@@ -74,62 +74,6 @@ public sealed class ResourceCleanupGroupTests
         Assert.Equal(2, releases);
     }
 
-    [Fact]
-    public void WorldRenderFoundationConstructorsPublishEveryOwnedPrefix()
-    {
-        string root = FindRepoRoot();
-        string graphicsDevice = File.ReadAllText(Path.Combine(
-            root,
-            "src",
-            "AcDream.App",
-            "Rendering",
-            "Wb",
-            "OpenGLGraphicsDevice.cs"));
-        string shader = File.ReadAllText(Path.Combine(
-            root,
-            "src",
-            "AcDream.App",
-            "Rendering",
-            "Wb",
-            "GLSLShader.cs"));
-        string uniformBuffer = File.ReadAllText(Path.Combine(
-            root,
-            "src",
-            "AcDream.App",
-            "Rendering",
-            "Wb",
-            "ManagedGLUniformBuffer.cs"));
-
-        AssertAppearsInOrder(
-            graphicsDevice,
-            "var resources = new ResourceCleanupGroup();",
-            "InstanceVBO = CreateConstructionBuffer(resources",
-            "WrapSampler = CreateConstructionSampler(",
-            "ClampSampler = CreateConstructionSampler(",
-            "_sceneDataBuffer = new ManagedGLUniformBuffer(",
-            "resources.Add(",
-            "\"WB scene-data uniform buffer\"",
-            "InitializeSharedDebugResources(resources);",
-            "resources.TransferAll();",
-            "resources.RollbackConstructionAndThrow(");
-        AssertAppearsInOrder(
-            shader,
-            "ShaderProgramConstruction.Build(",
-            "resources.Add(\"WB shader program\"",
-            "configure shader {Name} SceneData binding",
-            "resources.TransferAll();",
-            "resources.RollbackConstructionAndThrow(");
-        AssertAppearsInOrder(
-            uniformBuffer,
-            "TrackedGlResource.CreateBuffer(",
-            "resources.Add(",
-            "TrackedGlResource.AllocateBufferStorage(",
-            "resources.TransferAll();",
-            "resources.RollbackConstructionAndThrow(");
-        Assert.Contains("internal void DisposeImmediately()", uniformBuffer,
-            StringComparison.Ordinal);
-    }
-
     /// <summary>
     /// Campaign V slice V4a moved TextRenderer's constructor off raw
     /// VAO/VBO/texture GL names and onto two device-owned resources — a
@@ -176,49 +120,6 @@ public sealed class ResourceCleanupGroupTests
         return count;
     }
 
-    [Fact]
-    public void ReturnedNameIsRetainedWhenPostconditionAndFirstRollbackFail()
-    {
-        bool deleteFails = true;
-        int deleteCalls = 0;
-
-        GlResourceConstructionException failure =
-            Assert.Throws<GlResourceConstructionException>(() =>
-                GlResourceCommand.CreateNameCore(
-                    "synthetic buffer",
-                    static () => { },
-                    () => 42,
-                    () => throw new InvalidOperationException("postcondition failed"),
-                    name =>
-                    {
-                        Assert.Equal(42u, name);
-                        deleteCalls++;
-                        if (deleteFails)
-                            throw new InvalidOperationException("delete failed");
-                    }));
-
-        Assert.False(failure.IsCleanupComplete);
-        Assert.Equal(1, deleteCalls);
-
-        deleteFails = false;
-        failure.RetryCleanup();
-        failure.RetryCleanup();
-
-        Assert.True(failure.IsCleanupComplete);
-        Assert.Equal(2, deleteCalls);
-    }
-
-    private static void AssertAppearsInOrder(string source, params string[] values)
-    {
-        int cursor = -1;
-        foreach (string value in values)
-        {
-            int next = source.IndexOf(value, cursor + 1, StringComparison.Ordinal);
-            Assert.True(next > cursor, $"Missing or out-of-order source fragment: {value}");
-            cursor = next;
-        }
-    }
-
     private static string FindRepoRoot()
     {
         DirectoryInfo? directory = new(AppContext.BaseDirectory);