Explicitly separate public and private APIs

### What needs to get done

Right now it's hard to know what's public and what's private. For example, the `launchpad` and `remote` modules are probably mostly private, but it's not explicit.

### Why it needs to get done

We want to prevent every change from becoming a breaking change.

The issue names the launchpad and remote modules; start by inspecting how those modules are exposed and reviewing the package's current public surface. Identify the intended public and private boundaries, then confirm that the resulting separation makes it clear which changes can be treated as breaking API changes.

Written by the indexing model from the issue text.