MobX-State-Tree Prebuilt Middlewares

mst-middlewares provides a collection of prebuilt middlewares for MobX-State-Tree (MST), primarily serving as examples and starting points for developers to create their own custom MST middlewares. Originally part of the `mobx-state-tree` monorepo, it was extracted into its own package to keep the core MST library small. The package is currently at version 6.1.0 and appears to have a release cadence driven by contributions and fixes, with a recent major bump to v6.0.0. Key differentiators include its direct lineage from the official MST repository, offering basic but functional examples like action logging and transactional rollbacks, and encouraging direct modification or copy-pasting of its source for specific project needs rather than relying on them as fully-fledged, heavily-supported features. Developers are encouraged to read the source code to understand how to implement custom middleware for MST's event system.