R1:b5a009337f8e

Harbormaster v(-2)

Summary:
Ref T1049. I don't really want to sink too much time into this right now, but a seemingly reasonable architecture came to me in a dream. Here's a high-level overview of how things fit together:

- **"Build"**: In Harbormaster, "build" means any process we want to run against a working copy. It might actually be building an executable, but it might also be running lint, running unit tests, generating documentation, generating symbols, running a deploy, setting up a sandcastle…