Review fixes for 11.4 and 11.4b

ubuntu.sh takes Ubuntu 24.04 and its derivatives alone, since the DEB
names 24.04's t64 libraries. nixos.sh installs the newest release's
tag, not main. The release workflow refuses a tag that names another
version than the build files, and runs on the Node 24 actions.
DistortTests pins Swift's division by w past the horizon.

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

src/Document/Distort.cpp

@@ -16,7 +16,7 @@ extern "C" {
 }
 
 namespace {
-// Swift divides by w whatever its sign; Qt 6.11 clips.
+// Swift divides by w whatever its sign; Qt 6.10 clamps.
 QPointF project(const QTransform &map, QPointF point)
 {
     const double w = map.m13() * point.x() + map.m23() * point.y() + map.m33();