[Xoppyc]

Summary

• Align edge lines to arrowheads: Previously, edge Bezier curves ended directly at the node's left edge (to.x). Because the curve was still bending over the arrowhead's length, the incoming line visually drifted and entered the back of the horizontal arrow off-center. Edges now stop ARROW_SIZE (8px) before the node, connecting straight into the base of the arrowhead.
• Inherit edge colors on markers: Changed <marker> path fill from currentColor to context-stroke so arrowheads actually inherit the edge's dynamic stroke color (signals/effects/selection) instead of falling back to the SVG container's text color.
• Preserve active scaling without piercing nodes: Added a dedicated #solid-reactivity-arrow-active marker with an adjusted refX offset so highlighted arrows scale up nicely while remaining pinned to the node boundary.
• Update unit tests: Updated layout.test.ts to account for ARROW_SIZE in edgePath.

Before

After

[Xoppyc]

Grew a bit out of scope from just fixing the misalignment (as you can see from the branch name), but while I was in here I couldn't resist fixing the arrow coloring bug too

[lxsmnsyc]

I always forget to fix this so this change is welcome. Approved.