[Fix] (DirectVulkan): stop loading and carrying dead default-framebuffer content

- EGL swap semantics make the presented colour buffer's content undefined at
  its next acquire (EGL_BUFFER_DESTROYED, the implementation default) and
  every ancillary depth/stencil buffer's content undefined after ANY swap,
  yet the default-FBO render pass reloaded both with LOAD_OP_LOAD every
  frame; SwapchainObject now tracks per-image content validity (defined when
  a pass stores into the attachment, invalidated at present) and the
  render-pass manager turns an undefined attachment's tile load into
  LOAD_OP_DONT_CARE with initialLayout=UNDEFINED, keyed into both hashes so
  the cached LOAD variants cannot be hit by mistake
- the default framebuffer's depth attachment is now attached ON DEMAND: a
  draw with depth test and stencil test both disabled (GL: a disabled test
  neither reads nor writes its buffer), and no pending depth/stencil clear,
  resolves to a depth-less pass flavour, dropping the D24S8 tile load AND
  store outright - MC 26.2 renders its GUI into its own FBO and only ever
  blits colour to the default framebuffer, so its swapchain pass carried a
  full-screen depth round-trip for nothing
- the flavour only escalates: an active depth-full pass absorbs depth-less
  draws unchanged, while a depth-using draw against a depth-less pass
  resolves to an incompatible entry and splits, its depth loading DONT_CARE
  (the content was undefined all along); the depth-less flavour is folded
  into ComputeHash and the per-draw fast-path memo so the two flavours can
  never alias

MobileGL/MG_Backend/DirectVulkan/Renderer/SwapchainObject.h

@@ -52,6 +52,21 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         void SetImageLayout(Uint32 index, VkImageLayout layout);
         SizeT GetImageCount() const { return m_images.size(); }
 
+        // EGL content-validity tracking for the default framebuffer. A color
+        // buffer's content is undefined once its image has been presented
+        // (EGL_BUFFER_DESTROYED swap behaviour, the implementation default),
+        // and every ancillary (depth/stencil) buffer's content is undefined
+        // after ANY swap regardless of swap behaviour (EGL 1.5 §3.10.1). The
+        // render-pass manager turns an undefined attachment's tile load into
+        // LOAD_OP_DONT_CARE. Flags start false (a fresh swapchain image holds
+        // garbage) and a render pass storing into an attachment sets it back
+        // to defined.
+        Bool IsImageContentDefined(Uint32 index) const;
+        void SetImageContentDefined(Uint32 index, Bool defined);
+        Bool IsDepthStencilContentDefined(Uint32 index) const;
+        void SetDepthStencilContentDefined(Uint32 index, Bool defined);
+        void SetAllDepthStencilContentUndefined();
+
     private:
         void CreateImageViews(VkDevice device);
         void CreateDepthStencilResources(VkDevice device, VkPhysicalDevice physicalDevice);
@@ -77,5 +92,7 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         Vector<VkDeviceMemory> m_depthStencilImageMemories;
         Vector<VkImageView> m_depthStencilImageViews;
         Vector<VkImageLayout> m_depthStencilImageLayouts;
+        Vector<Bool> m_imageContentDefined;
+        Vector<Bool> m_depthStencilContentDefined;
     };
 } // namespace MobileGL::MG_Backend::DirectVulkan