fix(ci): pass --pre to pip download for winsdk beta wheels

The single pip-download call regressed winsdk fetching because pip
won't pick up pre-releases (1.0.0bNN) without --pre. The old per-dep
loop hid this via its fallback branch. Add --pre to both branches.

build-dist-windows.sh

@@ -73,12 +73,13 @@ ALL_DEPS=("${CORE_DEPS[@]}" "${WIN_DEPS[@]}" "${VIS_DEPS[@]}")
 if [ -d "$WHEEL_DIR" ] && [ -n "$(ls -A "$WHEEL_DIR" 2>/dev/null)" ]; then
     echo "Using cached wheels from $WHEEL_DIR"
 else
-    # Single pip-download call — pip resolves all deps together, much faster than a loop
-    pip download --quiet --dest "$WHEEL_DIR" \
+    # Single pip-download call — pip resolves all deps together, much faster than a loop.
+    # --pre is required because winsdk only ships beta wheels (1.0.0bNN).
+    pip download --pre --quiet --dest "$WHEEL_DIR" \
         --platform win_amd64 --python-version "${PYTHON_SHORT}" \
         --implementation cp --only-binary :all: \
         "${ALL_DEPS[@]}" 2>/dev/null || \
-    pip download --quiet --dest "$WHEEL_DIR" \
+    pip download --pre --quiet --dest "$WHEEL_DIR" \
         --only-binary :all: \
         "${ALL_DEPS[@]}"
 fi