Merge pull request 'rotation bug fixed' (#9) from jingwen_main into qinyue_main

Reviewed-on: #9

frontend/canvas-helpers.js

@@ -1282,6 +1282,22 @@ bundles:${groupsYaml ? `\n${groupsYaml}` : ' {}'}`;
     return null;
   };
 
+  const getRotatableNodeHandleDirection = (node, handleId) => {
+    if (!node || !handleId) return null;
+    if (node.type !== 'rotatableNode' && !(!node.data?.elementType && node.data?.componentName)) return null;
+    const ports = node.data && node.data.ports;
+    if (!ports || !ports[handleId]) return null;
+    const boxSize = normalizeBoxSize({ box_size: node.data && node.data.boxSize }, DEFAULT_COMPONENT_BOX_SIZE);
+    const handles = buildPortHandles(ports, {
+      rotation: Number((node.data && node.data.rotation) || 0),
+      flip: Boolean(node.data && node.data.flip),
+      flop: Boolean(node.data && node.data.flop),
+      boxSize
+    });
+    const found = handles.find(handle => handle.name === handleId);
+    return found ? found.position : null;
+  };
+
   // Backward-compatible alias for same-type route crossing validation.
   const findSameFamilyRouteCrossing = findSameTypeRouteCrossing;
 
@@ -1324,6 +1340,7 @@ bundles:${groupsYaml ? `\n${groupsYaml}` : ' {}'}`;
     createComponentSymbolMetrics,
     transformPortInfo,
     getNodePortCanvasPoint,
+    getRotatableNodeHandleDirection,
     buildPortHandles,
     buildElementPorts,
     buildElementPinEntries,