Edge rendering details

[kazcw]

• Fix output ports anti-aliasing: The end-caps and variable-width portions of output ports are separate objects in order to efficiently tie the variable-width portion to the node's width. They need to overlap each other and the node in order to avoid apparent gaps due inexact FP math and antialiasing.
• Z-order: A disconnected edge should render above nodes (except the attached node); target-attachment segments should be rendered above nodes. As individual components of an SVG object cannot be given different Z-indexes, objects that need different stacking should be rendered by separate component instantiations. (Target attachments could be drawn by the nodes, but they'll need the coloring information computed for rendering the edges.)

[farmaazon]

Refinement notes:

• In the connected edges, "above node" could be just a part of the port.
• In general, the path of the edge should just start where the node ends.

[kazcw]

The issues:

Incoming edge is not drawn above node background:

Disconnected edge is not drawn above other nodes:

[enso-bot]

Keziah Wesley reports a new STANDUP for yesterday (2024-02-14):

Progress: Implemented edge layering for target-attachment bits and unconnected edges. It should be finished by 2024-02-14.

Next Day: Next day I will be working on the #8238 task. Address review on code-editor PR.