Font: make atlas uploads queue-aware on Vulkan

Goal
----
Avoid corrupting the dynamic font-atlas on Vulkan by blocking any
re-uploads until the command buffer that created / last updated the
texture has actually been submitted.

What changed
------------
* **Queue-aware textures**
  * Added `queueSubmitAware` flag to `IDevice::CreateTexture*` APIs.
  * `Vulkan::CTexture` now stores two booleans:
      - `m_QueueSubmitAware` – opt-in per texture.
      - `m_PendingQueueSubmit` – set to *true* the moment an upload
        is recorded, cleared once the submit scheduler has flushed.
  * `CRingCommandContext::ScheduleUpload` marks the texture as
    pending (`SetPendingQueueSubmit(true)`).

* **Device-side watcher**
  * `Vulkan::CDevice` keeps a
    `m_TextureUploadWatcherQueue`. Each frame it checks textures that
    were uploaded ≥ `NUMBER_OF_FRAMES_IN_FLIGHT` frames ago and
    clears their pending flag.
  * New helpers
    `ScheduleTextureUploadWatch `,
    `ProcessTextureUploadWatchQueue()`.

* **Font code**
  * Atlas texture is now created with
    `queueSubmitAware = true`.
  * `CFont::UploadTextureAtlasToGPU()` early-outs when
    `IsPendingQueueSubmit()` returns *true*, instead of tracking a
    submit-handle or the manual `m_IsLoadingTextureToGPU` flag
    (removed).

Why this is better
------------------
The logic to wait for a flush is localised inside the rendering
backend, so `CFont` only needs to ask *“is my texture busy?”*.
This removes the fragile submit-handle bookkeeping and works even if
the scheduler issues multiple submits per frame in future.

Result
------
Atlas uploads are deferred until the previous submit completes,
eliminating the intermittent glyph corruption on the Vulkan backend
while leaving GL and the dummy backend unchanged.

source/graphics/Font.cpp

@@ -26,7 +26,9 @@
 #include "ps/Profiler2.h"
 #include "ps/containers/Span.h"
 #include "renderer/Renderer.h"
+#include "renderer/backend/Backend.h"
 #include "renderer/backend/IDevice.h"
+#include "renderer/backend/vulkan/Device.h"
 #include "renderer/backend/IDeviceCommandContext.h"
 #include "renderer/backend/ITexture.h"
 #include "renderer/backend/Sampler.h"
@@ -288,7 +290,7 @@ bool CFont::ConstructTextureAtlas()
 		Renderer::Backend::ITexture::Usage::TRANSFER_DST |
 		Renderer::Backend::ITexture::Usage::SAMPLED,
 		m_TextureFormat,
-		textureSize, textureSize, defaultSamplerDesc
+		textureSize, textureSize, defaultSamplerDesc, 1, 1, true
 	));
 
 	if (!m_Texture)
@@ -297,8 +299,6 @@ bool CFont::ConstructTextureAtlas()
 		return false;
 	}
 
-	m_IsLoadingTextureToGPU = true;
-
 	// Initialise texture with transparency, for the areas we don't
 	// overwrite with uploading later.
 	m_TexData = std::make_unique<u8[]>(m_AtlasSize);
@@ -493,10 +493,7 @@ std::optional<CVector2D> CFont::GenerateGlyphBitmap(FT_Glyph& glyph, u16 codepoi
 
 void CFont::UploadTextureAtlasToGPU()
 {
-	if (std::exchange(m_IsLoadingTextureToGPU, false))
-		return;
-
-	if (!m_IsDirty)
+	if (m_Texture->GetBackendTexture()->IsPendingQueueSubmit() || !m_IsDirty)
 		return;
 
 	Renderer::Backend::IDeviceCommandContext* deviceCommandContext = g_Renderer.GetDeviceCommandContext();