Font resize controls not working in diagram viewer

[RichardHightower]

Description

Font size A+/A- controls in the diagram toolbar do not change the diagram text size when clicked.

Steps to Reproduce

1. Open Skill Debugger
2. Navigate to any skill's Diagram tab
3. Click the A+ or A- buttons in the toolbar
4. Observe that diagram text size does not change

Expected Behavior

Clicking A+ should increase diagram text size, A- should decrease it, and Reset should return to 14px default.

Actual Behavior

Buttons click but have no visible effect on the diagram.

Technical Context

• Component: DiagramToolbar, FontSizeControls, InteractiveDiagram
• Files: src/components/diagram/DiagramToolbar.tsx, src/components/diagram/FontSizeControls.tsx, src/components/diagram/InteractiveDiagram.tsx
• Suspected issue: Font size state may not be propagating correctly to SVG elements, or app needs rebuild to pick up changes

Related

Part of diagram improvements in Feature 003 (Keyboard Shortcuts)