Command for a single type check over the monorepo

[turadg]

What is the Problem Being Solved?

Type checking one package is unnecessarily slow. Each package is treated separately wrt type definitions. They import from each other and with 2-3 depth so they end up repeating lots of parsing and inference.

Type checking the whole repo is very slow. yarn lint:types uses Lerna to run in each package. It takes ~2 minutes on my M1 Pro. I think a unified project would be order of 10x faster.

Package-based workflow misses errors. While working in a package you type-check there and we've been known to not notice errors introduced until CI errors, which is a slow feedback cycle. You can remember to check other packages, but that requires more command executions and you might not know all of them. Running over the whole repo takes minutes.

Description of the Design

A root tsconfig file as in #4404
Include at least one package having stricter rules than the root.

While we're at it, flip the ts-check from opt-in to opt-out for .js.

Security Considerations

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Test Plan

TBD