Add more viewer features

[dementive]

Summary

• Add configurable stock rendering with fixed dimensions, allowances, wall/floor stock, offsets, camera framing, and semantic wireframe edges. Allows viewer consumers to pass in custom stock geometry if they need to.
• Add direction-based face highlights, selection-driven X-ray focus, hover cards, and improved picking behavior.
• Add a section-plane gizmo with bidirectional dragging, physical cut measurement, and direction-coloured handles with theme overrides.
• Add the bundled banana-for-scale model and a viewer-scoped, composable toolbar with reusable styling.
• Update the React viewer example and browser coverage for the new controls and interactions.
• Add different viewer control settings based on the user's preferred CAD program.

Public package release

• Changesets are included for @toolpath/viewer.
• No breaking changes.

[BradEstey]

Can we document the class names and data-* props in the README and make sure every element has a class name; Components like ViewerToolbar.Viewer and HoverCard are missing them.

[BradEstey]

Also remove the "Click end, vertex, end · Shift locks an axis · Del removes last · Esc drops" explanation from measure tool. Merge measure and section view panels together. Hide cut depth label. Remove clear cut text and use trash icon. Add trash icon button to measure. Make distance/angle a toggle.

[BradEstey]

I wonder if toolbar may need to be its own package actually. It would be nice if it used the @toolpath/ui components but I wouldn't want to make @toolpath/ui as dependency of @toolpath/viewer.

done