## Changes
We had a number of copies of test helpers for `io/fs` in the repository.
This change consolidates all of them to use the `libs/fakefs` package.
## Tests
Unit tests pass.
## Changes
Whether or not the CLI is running on DBR can be detected once and stored
in the command's context.
By storing it in the context, it can easily be mocked for testing.
This builds on the simpler approach and conversation in #1744. It
unblocks testing of the DBR-specific paths while not compromising on the
checks we can perform to test if the CLI is running on DBR.
## Tests
* Unit tests for the new `dbr` package
* New unit test for the `ConfigureWSFS` mutator
Pieter Noordhuis