feat(O-T3): extract GL infrastructure to AcDream.App

Phase O Task 3 — verbatim-copy GL infra from Chorizite.OpenGLSDLBackend
into src/AcDream.App/Rendering/Wb/ (namespace AcDream.App.Rendering.Wb).

18 files extracted (all namespace-changed; no algorithm changes):
  OpenGLGraphicsDevice, ManagedGLTexture, ManagedGLTextureArray,
  ManagedGLVertexBuffer, ManagedGLIndexBuffer, ManagedGLVertexArray,
  ManagedGLFrameBuffer, ManagedGLUniformBuffer, GLSLShader, GLHelpers,
  GLStateScope, GpuMemoryTracker, SceneData, DebugRenderSettings,
  TextureParameters, TextureFormatExtensions, BufferUsageExtensions,
  EmbeddedResourceReader.

3 internals promoted to public (O-D9):
  EmbeddedResourceReader, TextureFormatExtensions, BufferUsageExtensions.

SixLabors.ImageSharp not reachable: TextureHelpers was placed in
AcDream.Core (no GL/ImageSharp dep); only the GL types went to App.

TextureHelpers.GetCompressedLayerSize added to AcDream.Core.Rendering.Wb
(was in Chorizite.OpenGLSDLBackend.Lib.TextureHelpers; uses
Chorizite.Core.Render.Enums.TextureFormat which Core gets transitively
via the still-present WB project refs).

T3/T4 boundary interims:
  - WbMeshAdapter._graphicsDevice stays Chorizite.OpenGLSDLBackend.OpenGLGraphicsDevice
    (T4 will swap it when ObjectMeshManager is extracted).
  - OpenGLGraphicsDevice.ParticleBatcher deferred to null! (T4 extracts
    ParticleBatcher alongside ObjectMeshManager; can't pass `this` of our
    new type to the WB-original ctor before T4).
  - ManagedGLTextureArray uses our TextureHelpers via explicit alias.
  - IUniformBuffer is in Chorizite.Core.dll under Chorizite.OpenGLSDLBackend
    namespace (unusual packaging); resolved via type alias.
  - AcDream.App.csproj gets explicit Chorizite.Core 0.0.18 PackageReference
    (IUniformBuffer + other Chorizite.Core types now used directly in App).

Build green. Test baseline 1147+8 maintained (1902 passing, 8 pre-existing
MotionInterpreterTests failures unrelated to T3).

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/AcDream.App/Rendering/Wb/ManagedGLVertexArray.cs

@@ -0,0 +1,77 @@
+using Chorizite.Core.Render.Enums;
+using Chorizite.Core.Render.Vertex;
+using Silk.NET.OpenGL;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+using VertexAttribType = Silk.NET.OpenGL.VertexAttribType;
+
+namespace AcDream.App.Rendering.Wb {
+    public unsafe class ManagedGLVertexArray : IVertexArray {
+        private readonly OpenGLGraphicsDevice _device;
+        private GL GL => _device.GL;
+        private uint _vaoId = 0;
+
+        public ManagedGLVertexArray(OpenGLGraphicsDevice device, IVertexBuffer buffer, VertexFormat format) {
+            _device = device;
+
+            // Generate the vertex array
+            _vaoId = GL.GenVertexArray();
+            GLHelpers.CheckErrors(GL);
+
+            if (_vaoId == 0) {
+                throw new Exception("Failed to generate vertex array.");
+            }
+            GpuMemoryTracker.TrackResourceAllocation(GpuResourceType.VAO);
+
+            SetVertexBuffer(buffer, format);
+        }
+
+        public void SetVertexBuffer(IVertexBuffer buffer, VertexFormat format) {
+            GL.BindVertexArray(_vaoId);
+            GLHelpers.CheckErrors(GL);
+            buffer.Bind();
+            for (int i = 0; i < format.Attributes.Length; i++) {
+                var attr = format.Attributes[i];
+                GL.EnableVertexAttribArray((uint)i);
+                GLHelpers.CheckErrors(GL);
+                GL.VertexAttribPointer((uint)i, attr.Size, Convert(attr.Type), attr.Normalized, (uint)format.Stride, attr.Offset);
+                GLHelpers.CheckErrors(GL);
+            }
+            GL.BindVertexArray(0);
+            GLHelpers.CheckErrors(GL);
+        }
+
+        private GLEnum Convert(Chorizite.Core.Render.Enums.VertexAttribType type) => type switch {
+            Chorizite.Core.Render.Enums.VertexAttribType.Float => GLEnum.Float,
+            Chorizite.Core.Render.Enums.VertexAttribType.Int => GLEnum.Int,
+            Chorizite.Core.Render.Enums.VertexAttribType.UnsignedInt => GLEnum.UnsignedInt,
+            Chorizite.Core.Render.Enums.VertexAttribType.UnsignedByte => GLEnum.UnsignedByte,
+            Chorizite.Core.Render.Enums.VertexAttribType.Byte => GLEnum.Byte,
+            _ => throw new NotSupportedException()
+        };
+
+        public void Bind() {
+            GL.BindVertexArray(_vaoId);
+            GLHelpers.CheckErrors(GL);
+        }
+
+        public void Unbind() {
+            GL.BindVertexArray(0);
+            GLHelpers.CheckErrors(GL);
+        }
+
+        public void Dispose() {
+            _device.QueueGLAction(GL => {
+                if (_vaoId != 0) {
+                    GL.DeleteVertexArray(_vaoId);
+                    GpuMemoryTracker.TrackResourceDeallocation(GpuResourceType.VAO);
+                    _vaoId = 0;
+                }
+                GLHelpers.CheckErrors(GL);
+            });
+        }
+    }
+}