[Dogfooding] Auto-refactor

[brillout]

This refactor was 🚀:

• Simplification review, all 35 approved proposals, and the work queue drained #1536

Goal: let AI (almost) fully autonomously do these kind of refactoring. So that, as a human, I can focus on high-level flows, while the code is fully maintained and autonomously improves over time whenever the usage quota has capacity.

We already have some elements to achieve that, but it's all half-assed. I think it's possible, but it requires more work.