* Fix Vulkan render target readback orientation to match OpenGL behavior
* Add render target pass resumption after Vulkan shadow rendering
Ensure that Vulkan render targets resume rendering properly after shadow passes, particularly for off-screen targets like SCPUI's 3D previews, to prevent unintended content leakage onto the screen.
* Skip alpha writes for additive batched bitmaps in render targets to preserve coverage and prevent opaque artifacts.
* Add external subpass dependencies to Vulkan render passes to fix read/write hazards
Introduce explicit memory dependencies for color attachments sampled between passes to prevent flickering and graphical artifacts caused by read-after-write and write-after-read hazards.
* Support fractional alpha values in createColor function and preserve 0-255 compatibility
Fabian Woltermann
d0cefc87bd