Add Kinetic UI to libraries.json

[onefreeman1337]

Adds one entry: Kinetic UI, a GameMaker UI library.

It generates every panel, border, bar and highlight from primitives and colour maths at draw time instead of shipping sprites, so it is resolution independent from 480p to 4K on one code path, retheming is editing a palette, and it adds no texture page entry.

Two things stated up front, because neither is obvious from the diff and you may not want either:

• It is a paid asset ($29.99 on itch.io). I checked the 16 itch-hosted entries already in libraries.json and they are all free or name-your-own-price, so this would be the first paid entry. CONTRIBUTING.md doesn't address paid libraries either way — if the answer is no, say so and I'll close this, no hard feelings.
• It was written with AI assistance, which is disclosed on the store listing and I'm not going to omit it here to make the PR read better.

On the change itself: it's a surgical text insert, so the diff is 14 added lines and nothing else — I deliberately avoided a JSON.parse/stringify round-trip because that reformatted all 113 existing entries into a 200-line diff. Validated against utility/libraries-schema.json (required fields, additionalProperties, the tags and compatibility enums, the author-key and github/twitter patterns, and duplicate titles). Tags used are ui and graphics; compatibility is Studio 2.3, the newest value the schema offers.

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