Return nil from get-prev-sibling when the shape is no longer present in
the parent ordering so delete undo generation falls back to index-based
restore instead of crashing on invalid vector access.
* 🎉 Add tokens to plugins API documentation
And add poc plugin example
* 📚 Document better the tokens value in plugins API
* 🔧 Refactor token validation schemas
* 🔧 Use automatic validation in token proxies
* 🔧 Use schemas to validate token creation
* 🔧 Use multi schema for token value
* 🔧 Use schema in token api methods
* 🐛 Fix review comments
---------
Co-authored-by: Andrey Antukh <niwi@niwi.nz>
* ✨ Update function implementation
* ✨ Add tests for a new function implementation
* ✨ Update function usages according to new signature
* ✨ Update docstrings
* ✨ Use simpler assertion
* 💄 Replace concat with cons on name-seq
* 🐛 Fix incorrect error handling on legacy workspace redirect
---------
Co-authored-by: Andrey Fedorov <oran9e.red@gmail.com>
