v0.7.4

Changed

• Refreshed every pinned PyPA manylinux/musllinux base image to the
  2026.09.29-1 upstream build. This updates all 34 entries in
  pinned_pypa_images.toml, including the nine images Dependabot reported,
  and synchronizes the 14 direct runtime mirrors in
  pinned_docker_images.toml. The remaining image-group pins are immutable
  cibuildmp GHCR digests and were deliberately left untouched.