end-to-end tests for type-safe bundling and serving

[afoxman]

Validate that type-safe bundling and serving both detect platform-specific errors. Use https://github.com/afoxman/rnts-example GitHub repo as an example.

[afoxman]

Also add automation for basic scenarios. For example, new project, just turned on bundling with all the defaults. It's not a TypeScript app -- just a regular JS app. TS validation should quietly do nothing (today it fails, which is being fixed now).

Common scenarios like that need to be validated. Not just this one example.