3D Character Emotion System

I want a custom framework that drives emotions and resulting behaviors for a small interactive 3D character. The system should:

• Maintain discrete mood states using a clean, extensible state-machine or behavior-tree architecture.
• Support clear transitions between states (smooth, instant, or context-based—whichever is most maintainable and scalable).
• Be delivered as modular, well-structured code with thorough inline comments and concise API documentation.

A minimal demo scene should be included, featuring a placeholder 3D model reacting to at least two different stimuli and changing moods accordingly.
Acceptance is complete once I can integrate the module into my project, add a new mood without editing core files, and see the expected behavior in the demo.

Required Skills:
• Strong Python or game-engine scripting (Unity C# or Unreal Blueprints/C++)
• Experience with state machines or behavior-tree systems
• Ability to write clean, modular, well-documented code

Preferred Skills:
• Animation or character-behavior experience
• AI/ML fundamentals.

Please include brief examples of relevant AI, behavior-tree, or emotion-system work.
Full project details will be provided after signing an NDA.