fix(archiso): chown work and output dirs back to user after mkarchiso

sudo mkarchiso leaves files owned by root, causing rm -rf to fail on re-runs.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

setup/archiso/build.sh

@@ -100,6 +100,7 @@ fi
 
 echo "Building ISO (this may take a while)..."
 sudo mkarchiso -v -w "$WORK_DIR/mkarchiso" -o "$OUT_DIR" "$PROFILE"
+sudo chown -R "$(id -u):$(id -g)" "$WORK_DIR" "$OUT_DIR"
 
 echo
 echo "Done."