Disable typechecking in CI

[Cang]

Currently, typechecking happens every time start, build, or test are executed. For development, this is standard and should be enforced. But for the CI environment, there is no need to typecheck over and over again with every command in the CI pipeline because the code does not change between steps.

If it's a CI environment, it makes sense to disable typechecking for start, build, and test and make typechecking its own step and done only once over the codebase within the CI environment, preferably before wasting CPU resources to run the other steps if it encounters a failure. This will improve performance of each CI run.

Typecheck will is still be enabled and enforced during the local development, nothing should change for the everyday development experience.

a modular typecheck command should exist to run typecheck over the project as an explicit action for CI steps.