[FEAT]: Allow users to choose AI model when filling forms

[marcvergees]

📝 Description

Enable users to select which AI model they want to use when filling out their form. This should be available via a dropdown button listing all available models.

💡 Rationale

Users may need different models for various tasks or preferences. Allowing selection increases flexibility and customizability.

🛠️ Proposed Solution

• Add a dropdown button to the form UI showing possible AI models
• When a model is selected for the first time, ensure it is installed as needed
• Manage state to track model installations and availability
• Store and manage user's model selection as a property

✅ Acceptance Criteria

• Users can choose from available AI models through a dropdown in the form
• When a model is selected and not installed, it gets installed automatically
• State of which models are installed and available is managed and persists appropriately
• Feature works in Docker container
• Documentation updated in docs/
• JSON output validates against the schema

📌 Additional Context

This enables dynamic extensibility for future models without manual intervention.