gui: speedup handling of bpins

[gadfort]

Changes:

• save bpins in rtree
• only compute boundingRect as needed.
• allow bpins to be selected

Before:

io pins setup 11.7252 sec
total render 19.7406 sec

After:

io pins setup 669.115 msec
total render 9.92228 sec (majority of this time is still drawing the arrows: 8.46995 sec)

[gemini-code-assist]

Code Review

This pull request significantly improves the performance of handling and rendering bpins by leveraging an r-tree for spatial queries, which is a great enhancement. The new feature to allow bpin selection is also a valuable addition. The code changes are generally well-structured. However, I've identified a critical performance and logic issue in setupIOPins concerning font size calculation, and another bug in drawIOPins that incorrectly prevents pin markers from being drawn. I have provided detailed comments and suggestions to address these points. With these fixes, the PR will be in excellent shape.

[gemini-code-assist]

This check incorrectly prevents IO pin markers from being drawn if pin names are not visible. The visibility of pin markers is controlled by areIOPinsVisible(), while the visibility of names is handled by the pin_draw_names_ flag later in the code. The || !viewer_->options_->areIOPinNamesVisible() part of the condition should be removed to ensure markers are drawn whenever IO pins are set to be visible, regardless of the name visibility setting.

  if (!viewer_->options_->areIOPinsVisible()) {

[github-actions]

clang-tidy made some suggestions