ToonJS: preparing 2.0 starts with contracts

Decisions and development

Phases A and B clarify what importing, transforming and serializing a table mean. Missing or invalid numeric values become NaN; column conflicts throw explicit errors and supported nested data is protected against external mutation.

The package keeps CommonJS and adds an explicit ESM wrapper. TypeScript NodeNext and Bundler resolution are checked from an installed tarball, alongside browser use through a bundler. Phase B logs show 455 passing tests and successful type, lint, build, coverage and packaging checks.