Add visual class expression builder

[aadorian]

Description

Stanford Protégé allows building complex class expressions. A visual builder would make this easier than typing Manchester Syntax.

What to implement

Create a form-based class expression builder:

• Select restriction type (some, only, min, max, exactly)
• Pick property from dropdown
• Pick filler class from dropdown
• Preview generated Manchester Syntax

Difficulty: Medium

Skills: React, OWL, Manchester Syntax

Tasks

• Create ClassExpressionBuilder component
• Add restriction type selector
• Add property and class pickers
• Generate Manchester Syntax from selections
• Add to class details panel

Acceptance Criteria

• Can build restrictions without typing syntax
• Preview shows Manchester Syntax
• Generated expressions are valid