timecraft: add integration test suite

[achille-roussel]

This PR sets up the infrastructure for integrations tests which exercise the main timecraft program, and

I moved the files from internal/cmd back into the top-level directory because I couldn't test the command by invoking cmd.Root because in some error cases the function calls os.Exit which is not permitted during a Go test, moving the tests exercising a compiled binary to internal/cmd did not feel right, and keeping the source and tests close seems like a better setup. We can move the sources back later if we address the os.Exit calls. Note that all the symbols are unexported and in the main package, so they cannot be imported by external Go packages.

I added tests for some of the commands but the test suite is not complete. It is already taking close to 1s to run, I believe this is likely due to recompiling the test wasm program in each test invoking timecraft run, I'll look into leveraging the caching capabilities of wazero to speed this up.

I made a few other changes as well, most are consistency and usability fixes that were highlighted by the test suite. I also added a --quiet option to simplify the text output to a single column of IDs, which is useful to implement script-like operations in tests that involve multiple invocations of the timecraft command.

[chriso]

🙈

[Pryz]

Curious why not follow the classic cmd folder like in any other project?

[achille-roussel]

Since this is intended to be a command, I want go install github.com/stealthrocket/timecraft to work.

If the main package is in a subdirectory, we need to do go install github.com/stealthrocket/timecraft/cmd/timecraft which is extra details that the user needs to know about the project layout to successfully build and install the program. go install happily says nothing when installing a non-main package, so it creates a pretty bad UX as the command appears to succeed but the program isn't actually installed.