Fix fallback arrow: derive position and angle from smooth-step path geometry

Author: milanofthe

src/lib/components/edges/OrthogonalEdge.svelte

@@ -505,13 +505,19 @@
 			return { x: endPoint.x, y: endPoint.y, angle };
 		}
 
-		// Fallback (smoothstep): arrow based on target position, use unadjusted target
-		let angle = 0;
-		if (targetPosition === 'left') angle = 180;
-		else if (targetPosition === 'top') angle = -90;
-		else if (targetPosition === 'bottom') angle = 90;
+		// Fallback (smoothstep): derive arrow position and angle from SVG path geometry
+		const { path } = pathInfo();
+		if (path) {
+			const svgPath = document.createElementNS('http://www.w3.org/2000/svg', 'path');
+			svgPath.setAttribute('d', path);
+			const totalLength = svgPath.getTotalLength();
+			const endPoint = svgPath.getPointAtLength(totalLength);
+			const nearEnd = svgPath.getPointAtLength(totalLength - 5);
+			const angle = Math.atan2(endPoint.y - nearEnd.y, endPoint.x - nearEnd.x) * (180 / Math.PI);
+			return { x: endPoint.x, y: endPoint.y, angle };
+		}
 
-		return { x: targetX, y: targetY, angle };
+		return { x: tgt.x, y: tgt.y, angle: 0 };
 	});
 </script>