0.6.0

Added

• YadaError enum and errors module with explicit error variants for build failures, by @kampersanda.
• Keyset validation in DoubleArrayBuilder::build: detects empty keysets, empty keys, keys containing NUL bytes, duplicate keys, unsorted keysets, values greater than 2^31 - 1, and tries exceeding 2^29 units, by @kampersanda.
• Default impl for DoubleArrayBuilder and Unit.
• Display impl for Unit.
• GitHub Actions CI: test (Linux x86/ARM, macOS, Windows), fmt, clippy, doc, and msrv jobs.
• GitHub Actions release workflow: SemVer tag pushes verify the version, run tests, publish to crates.io via Trusted Publishing (OIDC), and create a GitHub Release from the matching CHANGELOG.md section.
• RELEASE.md documenting the maintainer release procedure.
• rust-version = "1.58.0" in Cargo.toml.

Changed

• BREAKING: DoubleArrayBuilder::build now returns Result<Vec<u8>, YadaError> instead of Option<Vec<u8>>, by @kampersanda.
• Skip unnecessary recursion into leaf nodes during build, by @kampersanda.
• Update README MSRV from 1.46.0 to 1.58.0.

Removed

• BREAKING: Removed the stateful build_from_keyset API. Use DoubleArrayBuilder::build instead, by @kampersanda.