Add 3D-Agent to Code > AI (#467)

* Add 3D-Agent to the AI section

* Lead the 3D-Agent entry with its game-dev use (submission rules)

* 3D-Agent entry: name the engines it exports to

README.md

@@ -380,6 +380,7 @@ _Set of game frameworks, engines and platforms_
 - :tada: [ÖbEngine](https://github.com/Sygmei/ObEngine) - 2D Game Engine with Lua Scripting made on top of SFML !
 
 ### AI
+- :moneybag: [3D-Agent](https://3d-agent.com/blender-ai) - AI agent for game-ready 3D assets in Blender: models with clean quad topology and UVs, materials, rigs and animation from plain-language prompts, exported as FBX or GLB for Unity, Unreal and Godot. Also connects to Roblox Studio for scripts, assets and playtests, and builds FiveM / GTA V scenes.
 - :tada: [AI Game Developer](https://github.com/IvanMurzak/Unity-MCP) - `Unity Editor` and `Unity Runtime` AI integration. Unit Test, Coding, C# Roslyn, Reflection, Assets. Helps to create games with AI. And helps to run AI logic during gameplay.
 - :money_with_wings: [Coplay](https://coplay.dev?ref=github&utm_source=magictools) - AI Copilot for Unity
 - :tada: [Fluent Behaviour Tree](https://github.com/codecapers/Fluent-Behaviour-Tree) - C# behaviour tree library with a fluent API released under MIT.