Add Hover Focus Dimming Feature for Designer View

[cabaucom376]

Summary

Implements a visual feature that dims unrelated nodes and edges when hovering over tables in the Designer Table Graph, improving clarity of complex diagrams. Maybe closes #613.

Changes

• Added support for "dim" option in DiagramHoverFocus preference
• Implemented hover state tracking and class-based dimming (0.3 opacity)
• Added special handling for drag operations (temporarily disables dimming)
• Updated CSS to apply dimming to nodes, edges, and text labels

Testing

• Set Designer Hover Focus to "dim" in settings
• Hover over any table to see dimming effect
• Verify connected tables remain visible while others dim
• Confirm dimming is suspended during drag operations

[cabaucom376]

@macjuul, I’d like to get your thoughts on this. I just added a feature for recursively dimming relations. However, there are two different approaches to handling this.

1. Deeply recurse all nodes and display the entire relation tree.
2. Only recurse forward or backward in a more linear chain-like manner. (This is the approach I’ve chosen for now.)

I recognize the utility in both methods and may want to include an option for each. However, I’m not sure what naming conventions would be most intuitive for users. Additionally, I’m wondering if this is becoming too bloated or if it’s simply a naming convention issue.