[Perf] (MG_Backend/DirectVulkan, MG_State): stop re-deriving per-draw state

- Memoize the program content hash on ProgramObject (keyed by the backend
  state version + compile flags; relinking and binding changes invalidate
  it) and the vertex-input hash on VertexArrayObject (keyed by a new
  aggregate config version bumped by every attribute mutation). Full-SPIRV
  XXH64 hashing fell from 13.7% to 1.4% of the render thread.
- ProgramObject also gains a link version and a global-UBO content version
  (bumped by uniform writes and on relink, wrap-safe around the backends'
  "never uploaded" sentinel) for backends to gate uploads and link caches.
- Reuse member scratch vectors in SetupDraw, UploadAndBindVertexBuffers,
  GetOrCreatePipeline and BindProgramUniformBuffers instead of allocating
  per draw (~12% of render-thread time was in the allocator).
- Replace hot-path dynamic_cast with AsMipmapTexture (storage-type tag +
  static_cast); TextureObjectMipmap is the only Mipmap-tagged branch.
- Register/prune texture aliases only when a new (texture, lifetimeId)
  identity appears instead of scanning the entire alive map on every
  sampled-texture sync.
- Make the fallback VkPresentModeKHR log strings report the actual mode.

Vanilla render-thread share of libMobileGL dropped from 48% to 35% on
DirectVulkan (simpleperf, Adreno 830).

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

MobileGL/MG_Backend/DirectVulkan/Renderer/VulkanRenderer.h

@@ -272,6 +272,13 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         DepthMipmapResources m_depthMipmapResources;
         Vector<DeferredDepthMipmapCleanup> m_deferredDepthMipmapCleanup;
 
+        // Per-draw scratch buffers (clear keeps capacity) — these paths run for every
+        // draw call and must not allocate.
+        Vector<MG_State::GLState::ITextureObject*> m_sampledTexturesScratch;
+        Vector<VkBuffer> m_vertexBuffersScratch;
+        Vector<VkDeviceSize> m_vertexOffsetsScratch;
+        Vector<VkVertexInputAttributeDescription> m_patchedAttributesScratch;
+
         void CreateInstance();
         VkResult SetupDebugMessenger();
         VkResult DestroyDebugMessenger();