Feature Request: Support for self-hosted WordPress instances that are not via Automattic affiliates

### What

WordPress Studio looks great, but I don't use it because we don't use WordPress.com or Pressable for hosting and never will.

### Why

Because I'd love to rave about how cool this is, but the number of people (friends, family, clients et al) to whom I could recommend this is 1 instead of a couple hundred currently as they're not using WordPress.com or Pressable, and the overwhelming majority would never even humor the idea for a desktop app.

### How

_No response_

The issue identifies no files, tests, or entry points and provides no implementation details. Start by clarifying which self-hosted WordPress workflows WordPress Studio should support and where its current hosting assumptions are defined; done should be a documented, agreed support scope with tests covering the selected workflow.

Written by the indexing model from the issue text.