v0.16.0

• Updated compatibility for liboqs 0.16.0
• Breaking change: SPHINCS+ has been removed from liboqs 0.16.0. Users must migrate to SLH-DSA (FIPS 205)
• Added support for the ML-DSA external-mu variants ML-DSA-44-extmu, ML-DSA-65-extmu, and ML-DSA-87-extmu, which take a fixed 64-byte mu digest in place of the message
• Fixed a panic in Sign/Verify/SignWithCtxStr/VerifyWithCtxStr when passed an empty message, signature, or context string (zero-length slice dereference)
• liboqs 0.16.0 renames the existing FrodoKEM parameter sets to ephemeral FrodoKEM (efrodokem_*) and adds the salted variant under the original frodokem_* names
• Added an automated release workflow (release.yml) that is triggered by upstream liboqs and publishes a version-matched release once tests pass; see RELEASING.md
• Made the CI workflow reusable, pinned all GitHub Actions to commit hashes, and added an actionlint + zizmor lint gate for the workflow files
• Switched release tags to the Go module vX.Y.Z convention (e.g. v0.16.0), so the module can be fetched with go get github.com/open-quantum-safe/liboqs-go@v0.16.0