Improve labels and descriptions on hover for mechanical diagrams

[GeneralJerel]

Problem

When generating mechanical/engineering diagrams (e.g. car axle visualizations), the labels and descriptions are static and can clutter the diagram. Hover interactions would make the diagrams cleaner while keeping information accessible.

Current behavior

• All labels (e.g. "axle shaft", "splits torque", "vehicle load") are always visible
• Legend items at the bottom take up space
• Descriptive text is static

Proposed improvement

• Show concise labels by default, reveal detailed descriptions on hover
• Add hover tooltips to diagram components (wheels, differential, axle shafts)
• Consider collapsible legend or hover-triggered legend highlights
• Improve label positioning and readability for complex diagrams

Context

This came up when testing mechanical/engineering diagram generation — the widget renderer produces good visualizations but the information density could be better managed with interactive hover states.