Dedup in-repo toml/semver/cli/testing onto lwpt workspace packages

[frostney]

Summary

Replace in-repo toml / semver / cli / testing implementations with lwpt workspace packages.

Why

lwpt provides canonical toml, semver, cli, and testing packages; deduping onto them removes parallel maintenance of the same utilities.

Current behavior

The project carries its own implementations of these utilities.

Expected behavior

• The in-repo toml / semver / cli / testing code is replaced by the lwpt workspace packages at behavioural parity.

Scope notes

• The runtime TOML/YAML built-ins (JS-visible) are a separate concern and out of scope. Part of the lwpt migration (parent Migrate toolchain to lwpt #826).