GPU: Check post shaders once per host frame, after resizes

Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>

GPU/GPUCommon.cpp

@@ -75,6 +75,11 @@ void GPUCommon::BeginHostFrame(const DisplayLayoutConfig &config) {
 	CheckConfigChanged(config);
 	CheckDisplayResized();
 	CheckRenderResized(config);
+
+	// After the resizes, which ask for the post shaders to be rebuilt at the new size.
+	if (framebufferManager_) {
+		framebufferManager_->CheckPostShaders(config);
+	}
 }
 
 void GPUCommon::EndHostFrame() {

GPU/GPUCommonHW.cpp

@@ -416,11 +416,6 @@ void GPUCommonHW::CheckConfigChanged(const DisplayLayoutConfig &config) {
 		BuildReportingInfo();
 		configChanged_ = false;
 	}
-
-	// Check needed when running tests.
-	if (framebufferManager_) {
-		framebufferManager_->CheckPostShaders(config);
-	}
 }
 
 void GPUCommonHW::CheckDisplayResized() {