ci: move g++ warmup from test code to CI workflow

Cold-start mitigation belongs in the CI layer, not in test code.
The workflow now runs g++ before tests so the toolchain is already
in the OS file cache. Also removes QStandardPaths/QProcess
dependency that was only needed for the warmup.

Author: ZnPdCo

.github/workflows/windows-qt6.yml

@@ -80,6 +80,16 @@ jobs:
       - name: Deploy Qt for tests
         shell: pwsh
         run: windeployqt tests\test1\test1.exe
+      - name: Warm up g++ (cold-start mitigation)
+        shell: bash
+        run: |
+          gpp=$(which g++ 2>/dev/null || true)
+          if [ -n "$gpp" ]; then
+            echo "int main(){return 0;}" | g++ -x c++ -O2 -o "$TEMP/_warmup.exe" -
+            echo "g++ warmup done: $gpp"
+          else
+            echo "g++ not found, skipping warmup"
+          fi
       - name: Run tests
         shell: bash
         env:

tests/test1/main.cpp

@@ -159,20 +159,6 @@ class TestContest : public QObject {
 			}
 		};
 		copyDir(m_contestDir, dst, copyDir);
-
-		// Warm up g++: compile a trivial program to pay the cold-start cost
-		// upfront instead of during the timed judging test.
-		{
-			QString gppPath = QStandardPaths::findExecutable("g++");
-			if (!gppPath.isEmpty()) {
-				QProcess warmup;
-				warmup.start(gppPath, {"-x", "c++", "-O2", "-o",
-				              m_tempWorkDir.path() + "/_warmup.exe", "-"});
-				warmup.write("int main(){return 0;}");
-				warmup.closeWriteChannel();
-				warmup.waitForFinished(60000);
-			}
-		}
 	}
 
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