feat: rewording

frontend/src/core/i18n/locales/en-US.ts

@@ -214,7 +214,7 @@ export const enUS: Translations = {
   subtasks: {
     subtask: "Subtask",
     executing: (count: number) =>
-      `Executing ${count} subtask${count === 1 ? "" : "s"} in parallel`,
+      `Executing ${count === 1 ? "" : count + " "}subtask${count === 1 ? "" : "s in parallel"}`,
     in_progress: "Running subtask",
     completed: "Subtask completed",
     failed: "Subtask failed",

frontend/src/core/i18n/locales/zh-CN.ts

@@ -207,7 +207,8 @@ export const zhCN: Translations = {
 
   subtasks: {
     subtask: "子任务",
-    executing: (count: number) => `并行执行 ${count} 个子任务`,
+    executing: (count: number) =>
+      `${count > 1 ? "并行" : ""}执行 ${count} 个子任务`,
     in_progress: "子任务运行中",
     completed: "子任务已完成",
     failed: "子任务失败",