[CLI] Include the v0.4.0 base spec

[SnowboardTechie]

Summary

Once core v0.4.0 is released, update the CLI to include the new v0.4.0 base spec so cg check can validate implementations against it. The CLI bundles one spec file per protocol version in lib/cli/lib/openapi/ (currently 0.1.0 through 0.3.0), and the check command picks up available versions from that directory. Ship it as a minor release of the CLI.

Follow-up from the v0.4.0 hold branch review in #1040.

Acceptance criteria

• The v0.4.0 base spec is bundled with the CLI and selectable in cg check
• A minor version of the CLI is released with the new spec