chore: immaculate upgrade — add canonical tags, fix YAML front-matter, remove superlatives, downgrade SLSA L3→L1, update canonical numbers to 2026-05-30 (24/26/2/12/217/7/35/7/8.3%)

Update dataset card: pin uds-v0.3.0 release (sha256: 96a301140ef24c88...)

Upload a11oy-uds-0.3.0 source tarball (Doctrine v6, built 2026-05-29)

initial commit