perf(window): hoist invariant per-frame Vulkan info structs to members (#43)

Window::Render() rebuilt cmdBufInfo, the subresource range, both
VkImageMemoryBarrier structs, and presentInfo on the stack every frame
even though only the barriers' image (and the acquire barrier's
oldLayout) ever change. Hoist them to members initialised once in the
constructor; Render() now patches only the two varying fields.

presentInfo.pImageIndices/pSwapchains point at the currentBuffer and
swapChain members, so they track value changes (including swapchain
recreation) automatically. The render-complete wait semaphore is fixed
for the window's lifetime, so the per-frame `renderComplete != NULL`
check — set once, never cleared — was dead and is removed; the
semaphore is wired into presentInfo in the constructor instead.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

interfaces/Crafter.Graphics-Window.cppm

@@ -259,6 +259,16 @@ export namespace Crafter {
         std::thread thread;
         VkCommandBuffer drawCmdBuffers[numFrames];
         VkSubmitInfo submitInfo;
+        // Per-frame Vulkan info structs whose contents are almost entirely
+        // invariant. Initialised once in the constructor; Render() patches only
+        // the few fields that change each frame (the two barriers' image and
+        // the acquire barrier's oldLayout). presentInfo.pImageIndices and
+        // pSwapchains point at the currentBuffer/swapChain members, so they
+        // track value changes (including swapchain recreation) automatically.
+        VkCommandBufferBeginInfo cmdBufInfo;
+        VkImageMemoryBarrier acquireBarrier;
+        VkImageMemoryBarrier presentBarrier;
+        VkPresentInfoKHR presentInfo;
         Semaphores semaphores;
         std::uint32_t currentBuffer = 0;
         VkPipelineStageFlags submitPipelineStages = VK_PIPELINE_STAGE_COLOR_ATTACHMENT_OUTPUT_BIT;