CreateSwapchain unconditionally used VK_PRESENT_MODE_FIFO_KHR, but still
ran two vkGetPhysicalDeviceSurfacePresentModesKHR calls plus a heap-allocated
std::vector to enumerate present modes that were never consulted. Delete
them and assign the constant directly.
compositeAlpha is a surface property that does not change across swapchain
recreation, so select it once at construction instead of re-deriving it
(with another heap-allocated vector) on every resize configure. The
vkQueueWaitIdle before recreation is left intact as required.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
