fix: polish PARALLEL swimlanes and color-code edge conditions

Co-authored-by: Cursor <cursoragent@cursor.com>

src/stores/designer.ts

@@ -173,13 +173,18 @@ export const useDesignerStore = defineStore('designer', () => {
   }
 
   function syncStartFlags() {
+    const current = nodes.value.find((node) => node.id === startStepId.value)
+    if (current?.parentNode) {
+      startStepId.value = current.parentNode
+    }
     nodes.value = nodes.value.map((node) => {
       if (!node.data || node.data.kind === 'END') {
         return node
       }
+      const isStart = !node.parentNode && node.id === startStepId.value
       return {
         ...node,
-        data: { ...node.data, isStart: node.id === startStepId.value },
+        data: { ...node.data, isStart },
       }
     })
   }
@@ -694,7 +699,7 @@ export const useDesignerStore = defineStore('designer', () => {
     edges.value = edges.value.filter((edge) => !drop.has(edge.source) && !drop.has(edge.target))
   }
 
-  function addLaneStep(parallelId: string, lane: string) {
+  function addLaneStep(parallelId: string, lane: string, kind: 'approval' | 'action' = 'approval') {
     const parent = nodes.value.find((node) => node.id === parallelId)
     if (!parent || parent.data.kind !== 'PARALLEL' || !parent.data.lanes.includes(lane)) {
       return
@@ -702,7 +707,10 @@ export const useDesignerStore = defineStore('designer', () => {
     pushHistory()
     const laneIndex = parent.data.lanes.indexOf(lane)
     const stepIndex = nodes.value.filter((node) => node.parentNode === parallelId && laneOf(node.data) === lane).length
-    nodes.value = fitParallelFrames([...nodes.value, spawnLaneStep(parallelId, lane, laneIndex, stepIndex, nextId(lane))])
+    nodes.value = fitParallelFrames([
+      ...nodes.value,
+      spawnLaneStep(parallelId, lane, laneIndex, stepIndex, nextId(lane), kind),
+    ])
   }
 
   function renameLane(parallelId: string, from: string, to: string): boolean {