Fix Vulkan presenter synchronization and frame handling issues (#747)

* [VideoOut/Vulkan] Fix boot deadlock, writeback stall, and presentation bugs

- Presenter thread now starts on the compute dispatch path too, fixing
  a boot deadlock when a title's first GPU work is compute (Ghost of
  Yotei G-Buffer clear).
- Guest render-target format swaps between sibling pixel formats now
  reinterpret in place instead of recreating blank, preserving
  GPU-written content.
- Vectorized the guest-buffer writeback scan (equal-byte skip + coarse
  per-page pre-check), fixing multi-second stalls on fragmented buffers
  that starved JobWorker completion signals.
- _presentedSequence now advances on every Render() early-return path,
  fixing an unthrottled busy loop on stale/dropped presentations.

* Remove unnecessary Silk.NET.Windowing dependency

tests/SharpEmu.Libs.Tests/VideoOut/VulkanGuestImageAliasTests.cs

@@ -53,7 +53,6 @@ public sealed class VulkanGuestImageAliasTests
     }
 
     [Theory]
-    [InlineData(Format.R8Srgb, Format.R8Unorm)]
     [InlineData(Format.BC3SrgbBlock, Format.BC3UnormBlock)]
     public void CounterpartsOutsideTheViewClassTableAreNotAliased(
         Format existing,
@@ -68,6 +67,15 @@ public sealed class VulkanGuestImageAliasTests
             VulkanVideoPresenter.IsAliasableGuestImageFormat(existing, requested));
     }
 
+    [Fact]
+    public void R8SrgbAndR8UnormShareOneCompatibilityClass()
+    {
+        Assert.True(
+            VulkanVideoPresenter.IsCompatibleGuestImageViewFormat(
+                Format.R8Srgb,
+                Format.R8Unorm));
+    }
+
     [Fact]
     public void AliasedPairStaysWithinOneCompatibilityClass()
     {