This is a great project, and the documentation is beautiful.
I’ve also been aiming for this same goal in my conlanging efforts. I don’t like always having to go back to the reference materials to be able to work with a language I’m learning. I like the idea of having something where if I don’t know how to say something, I can figure it out by stepping through with what I know.
My biggest work in this direction is Snvsdr Dhv. It’s a bit different. Rather than a system of affixes, it has some inflections and combines them with an analytical system for combining words together.
The root words are all one syllable or less/ They can be inverted or reversed and marked with a tone to set part of speech. Verbs and nouns take accusative objects as suffixes, which can be chained. Then verbs can come afterwards as modifiers. Verb phrases are valid sentences, and can also be joined by connectives.
To illustrate how it works, I’ve drawn up a table of conversions from Luno Lei to Snvsdr Dhv for the word root “noka” (leg/walk → ŕmsdo/do).
And here’s my translation of your example sentence.
EDIT: I’ve moved some of the stuff from this comment to the Snvsdr Dhv thread because it was long.