fix: 消除保存并发竞态——同步锁防重复保存，冲突判定先比对内容

src/main/index.ts

@@ -129,14 +129,23 @@ function registerIpc(): void {
   });
   ipcMain.handle("flows:get", (_event, id: string) => getFlow(id));
   ipcMain.handle("flows:save", (_event, flow: FlowDefinition, opts?: FlowSaveOptions): FlowSaveResult => {
-  if (!opts?.force && opts?.expectedUpdatedAt) {
-    const disk = getFlow(flow.id);
-    if (disk && disk.meta?.updatedAt && disk.meta.updatedAt !== opts.expectedUpdatedAt) {
-      return { conflict: true, diskFlow: disk };
+    if (!opts?.force && opts?.expectedUpdatedAt) {
+      let disk: FlowDefinition | null = null;
+      try {
+        disk = getFlow(flow.id);
+      } catch {
+        disk = null; // 磁盘文件不存在或损坏时视为全新保存
+      }
+      if (disk && disk.meta?.updatedAt && disk.meta.updatedAt !== opts.expectedUpdatedAt) {
+        // 内容一致（仅 updatedAt 差异，如并发/重复保存）不视为冲突
+        const normalize = (item: FlowDefinition) => JSON.stringify({ ...item, meta: undefined });
+        if (normalize(disk) !== normalize(flow)) {
+          return { conflict: true, diskFlow: disk };
+        }
+      }
     }
-  }
-  return { conflict: false, flow: saveFlow(flow) };
-});
+    return { conflict: false, flow: saveFlow(flow) };
+  });
   ipcMain.handle("flows:delete", (_event, id: string) => {
     deleteFlow(id);
     return true;