[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.cpp

@@ -262,6 +262,9 @@ namespace MobileGL::MG_Backend::DirectVulkan {
         m_images.resize(imageCount, VK_NULL_HANDLE);
         VK_VERIFY(vkGetSwapchainImagesKHR(device, m_swapchain, &imageCount, m_images.data()));
         m_imageLayouts.assign(imageCount, VK_IMAGE_LAYOUT_UNDEFINED);
+        // Fresh swapchain images hold garbage until a render pass stores into them.
+        m_imageContentDefined.assign(imageCount, false);
+        m_depthStencilContentDefined.assign(imageCount, false);
 
         CreateImageViews(device);
         CreateDepthStencilResources(device, physicalDevice);
@@ -433,9 +436,39 @@ namespace MobileGL::MG_Backend::DirectVulkan {
 
         m_images.clear();
         m_imageLayouts.clear();
+        m_imageContentDefined.clear();
+        m_depthStencilContentDefined.clear();
         m_preTransform = VK_SURFACE_TRANSFORM_IDENTITY_BIT_KHR;
     }
 
+    Bool SwapchainObject::IsImageContentDefined(Uint32 index) const {
+        MOBILEGL_ASSERT(index < m_imageContentDefined.size(), "Swapchain image content index out of range");
+        return m_imageContentDefined[index];
+    }
+
+    void SwapchainObject::SetImageContentDefined(Uint32 index, Bool defined) {
+        MOBILEGL_ASSERT(index < m_imageContentDefined.size(), "Swapchain image content index out of range");
+        m_imageContentDefined[index] = defined;
+    }
+
+    Bool SwapchainObject::IsDepthStencilContentDefined(Uint32 index) const {
+        MOBILEGL_ASSERT(index < m_depthStencilContentDefined.size(),
+                        "Swapchain depth/stencil content index out of range");
+        return m_depthStencilContentDefined[index];
+    }
+
+    void SwapchainObject::SetDepthStencilContentDefined(Uint32 index, Bool defined) {
+        MOBILEGL_ASSERT(index < m_depthStencilContentDefined.size(),
+                        "Swapchain depth/stencil content index out of range");
+        m_depthStencilContentDefined[index] = defined;
+    }
+
+    void SwapchainObject::SetAllDepthStencilContentUndefined() {
+        for (SizeT i = 0; i < m_depthStencilContentDefined.size(); ++i) {
+            m_depthStencilContentDefined[i] = false;
+        }
+    }
+
     VkImage SwapchainObject::GetImage(Uint32 index) const {
         MOBILEGL_ASSERT(index < m_images.size(), "Swapchain image index out of range");
         return m_images[index];