Add versioned, cross-language Selene API models

[trvto]

Introduces the selene-protocol workspace for versioned, serializable Selene API models.

• Adds trace schema v0.1.0 plus Python, Rust, and TypeScript packages.
• Adds validation, examples, compatibility documentation, CI, Just recipes, and pre-commit coverage.
• Encodes all uint64 trace values as canonical decimal strings in JSON for cross-language precision safety.
• Coordinates package releases under a shared selene-api-models-v tag.

Before the first release, configure:

• A PyPI trusted publisher for selene-api-models, tied to this repository’s api_models.yml workflow.
• Repository secret CARGO_REGISTRY_TOKEN, authorized to publish selene-api-models on crates.io.
• Repository secret NPM_TOKEN, authorized to publish @quantinuum/selene-api-models on npm.