CI: build and run the unit tests in the Windows job

The Windows job configured with -DPACKAGE_TESTS=OFF, so no test ever ran
on Windows. Build the tests and run ctest after the build, with the
offscreen platform. ctest prints no output for failed tests in the MSYS2
shell, so each failed test runs again with QtTest writing its log to a
file, which is printed in its own log group. The ctest log is added to
the artifact uploaded on failure.

No change to the app or its files.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

.github/workflows/windows-build.yml

@@ -117,7 +117,7 @@ jobs:
             -DQT_VERSION_MAJOR=6 \
             -DBUILD_WITH_KF=ON \
             -DBUILD_KF=OFF \
-            -DPACKAGE_TESTS=OFF \
+            -DPACKAGE_TESTS=ON \
             -DCMAKE_POLICY_DEFAULT_CMP0077=NEW \
             -DCMAKE_POLICY_VERSION_MINIMUM=3.5 \
             -DQET_EXPORT_PROJECT_DB=ON \
@@ -136,6 +136,32 @@ jobs:
           echo "=== ccache statistics ==="
           /ucrt64/bin/ccache -s
 
+      - name: Run the unit tests
+        shell: msys2 {0}
+        env:
+          QT_QPA_PLATFORM: offscreen
+        run: |
+          set -euo pipefail
+          cd "$GITHUB_WORKSPACE/build"
+          ctest --output-on-failure --timeout 300 && exit 0
+          # ctest shows no output for failed tests in this shell, so run each
+          # failed test again with QtTest writing its log to a file, and print it.
+          set +e
+          while IFS=: read -r _ name; do
+            name=${name%$'\r'}
+            exe=$(find tests -name "$name.exe" | head -1)
+            echo "::group::$name"
+            if [ -n "$exe" ]; then
+              QT_QPA_PLATFORM=offscreen "$exe" -o "$name.txt,txt"
+              echo "exit code $?"
+              cat "$name.txt" 2>/dev/null
+            else
+              echo "no executable for $name"
+            fi
+            echo "::endgroup::"
+          done < Testing/Temporary/LastTestsFailed.log
+          exit 1
+
       - name: Verify exe was built
         shell: msys2 {0}
         run: |
@@ -436,6 +462,7 @@ jobs:
           name: build-logs-qt6
           path: |
             build/CMakeFiles/*.log
+            build/Testing/Temporary/LastTest*.log
             nsis_root/files/bin/
           if-no-files-found: warn