fix(dashboard): alternate feedback edges left/right (#247 Phase 2)

What: Feedback (back) edges now alternate between left and right sides
instead of all routing to the right.

Why: Multiple feedback edges targeting the same node (e.g. reviewer→coder
and tester→coder) were overlapping on the right side.

Changes:
- types.ts: add feedbackSide field to ConditionEdgeData
- use-layout.ts: track feedback count per target, alternate sides
- condition-edge.tsx: feedbackPath() accepts side param, mirrors path for left

Ref: #247, closes #249

packages/workflow-dashboard/src/components/workflow-graph/condition-edge.tsx

@@ -7,25 +7,23 @@ const FEEDBACK_OFFSET_X = 100;
 const FEEDBACK_RADIUS = 16;
 
 /**
- * Build an SVG path for a feedback (back) edge that routes to the right of the nodes.
- * The path goes: source right → arc → vertical up → arc → target right
+ * Build an SVG path for a feedback (back) edge that routes to the given side of the nodes.
+ * The path goes: source → arc → vertical up → arc → target
  */
-function feedbackPath(sourceX: number, sourceY: number, targetX: number, targetY: number): string {
-  const rightX = Math.max(sourceX, targetX) + FEEDBACK_OFFSET_X;
+function feedbackPath(sourceX: number, sourceY: number, targetX: number, targetY: number, side: "right" | "left"): string {
+  const d = side === "right" ? 1 : -1;
+  const offsetX =
+    side === "right"
+      ? Math.max(sourceX, targetX) + FEEDBACK_OFFSET_X
+      : Math.min(sourceX, targetX) - FEEDBACK_OFFSET_X;
   const r = FEEDBACK_RADIUS;
 
-  // Start from source right side, go right, then up, then left to target right side
   const segments = [
     `M ${sourceX} ${sourceY}`,
-    // Horizontal to the right
-    `L ${rightX - r} ${sourceY}`,
-    // Arc turning upward
-    `Q ${rightX} ${sourceY} ${rightX} ${sourceY - r}`,
-    // Vertical upward
-    `L ${rightX} ${targetY + r}`,
-    // Arc turning left
-    `Q ${rightX} ${targetY} ${rightX - r} ${targetY}`,
-    // Horizontal left to target
+    `L ${offsetX - d * r} ${sourceY}`,
+    `Q ${offsetX} ${sourceY} ${offsetX} ${sourceY - r}`,
+    `L ${offsetX} ${targetY + r}`,
+    `Q ${offsetX} ${targetY} ${offsetX - d * r} ${targetY}`,
     `L ${targetX} ${targetY}`,
   ];
 
@@ -57,10 +55,13 @@ export function ConditionEdge(props: EdgeProps) {
   let defaultLabelY: number;
 
   if (isFeedback) {
-    // Custom feedback path routed to the right
-    path = feedbackPath(sourceX, sourceY, targetX, targetY);
-    const rightX = Math.max(sourceX, targetX) + FEEDBACK_OFFSET_X;
-    defaultLabelX = rightX;
+    const side = edgeData?.feedbackSide ?? "right";
+    path = feedbackPath(sourceX, sourceY, targetX, targetY, side);
+    const offsetX =
+      side === "right"
+        ? Math.max(sourceX, targetX) + FEEDBACK_OFFSET_X
+        : Math.min(sourceX, targetX) - FEEDBACK_OFFSET_X;
+    defaultLabelX = offsetX;
     defaultLabelY = (sourceY + targetY) / 2;
   } else {
     const result = getSmoothStepPath({

packages/workflow-dashboard/src/components/workflow-graph/types.ts

@@ -23,6 +23,7 @@ export type ConditionEdgeData = {
   isFallback: boolean;
   isFeedback: boolean;
   isSelfLoop: boolean;
+  feedbackSide: "right" | "left" | null;
   labelX: number | null;
   labelY: number | null;
   [key: string]: unknown;

packages/workflow-dashboard/src/components/workflow-graph/use-layout.ts

@@ -173,6 +173,8 @@ function computeLayout(input: LayoutInput): LayoutResult {
   // Build edges with label positions
   // For feedback edges (target rank < source rank), we'll compute label at midpoint
   // of the right-side arc. The actual SVG path is drawn by ConditionEdge component.
+  // Track feedback edge count per target node for alternating sides
+  const feedbackCountByTarget = new Map<string, number>();
   const edges: Edge[] = input.edges.map((e) => {
     const isFallback = e.condition === "FALLBACK";
     const isSelfLoop = e.from === e.to;
@@ -185,13 +187,20 @@ function computeLayout(input: LayoutInput): LayoutResult {
 
     let labelX: number | null = null;
     let labelY: number | null = null;
+    let feedbackSide: "right" | "left" | null = null;
 
     if (sourcePos !== undefined && targetPos !== undefined) {
       if (isFeedback) {
-        // Label on the right side of the feedback arc
-        const rightX = centerX + ROLE_NODE_WIDTH / 2 + FEEDBACK_OFFSET_X;
+        // Alternate feedback edges left/right per target node
+        const count = feedbackCountByTarget.get(e.to) ?? 0;
+        feedbackCountByTarget.set(e.to, count + 1);
+        feedbackSide = count % 2 === 0 ? "right" : "left";
+        const offsetX =
+          feedbackSide === "right"
+            ? centerX + ROLE_NODE_WIDTH / 2 + FEEDBACK_OFFSET_X
+            : centerX - ROLE_NODE_WIDTH / 2 - FEEDBACK_OFFSET_X;
         const midY = (sourcePos.y + sourcePos.h / 2 + targetPos.y + targetPos.h / 2) / 2;
-        labelX = rightX;
+        labelX = offsetX;
         labelY = midY;
       } else if (!isSelfLoop) {
         // Forward edge: label between source bottom and target top
@@ -214,6 +223,7 @@ function computeLayout(input: LayoutInput): LayoutResult {
         isFallback,
         isFeedback,
         isSelfLoop,
+        feedbackSide,
         labelX,
         labelY,
       },