ci: avoid lockfile dependency in release version check

[mrcrgl]

Summary

• replace cargo pkgid release tag/version validation with direct Cargo.toml package-version parsing
• avoid lockfile dependency in the release workflow's version gate
• fail explicitly if package version cannot be read

Validation

• cargo fmt --all -- --check
• cargo clippy --all-features -- -D warnings
• cargo test --all
• cargo test --no-default-features
• ./scripts/release-check.sh

Closes #51