feat(i18n): add plural forms for agent and assistant labels

Add singular and plural forms for "agent" and "assistant" labels in both English and Chinese locales
Display plural labels in AssistantsTab component

src/renderer/src/i18n/locales/en-us.json

@@ -752,8 +752,11 @@
     "add": "Add",
     "add_success": "Added successfully",
     "advanced_settings": "Advanced Settings",
+    "agent_one": "Agent",
+    "agent_other": "Agents",
     "and": "and",
-    "assistant": "Assistant",
+    "assistant_one": "Assistant",
+    "assistant_other": "Assistants",
     "avatar": "Avatar",
     "back": "Back",
     "browse": "Browse",

src/renderer/src/i18n/locales/zh-cn.json

@@ -752,8 +752,12 @@
     "add": "添加",
     "add_success": "添加成功",
     "advanced_settings": "高级设置",
+    "agent_one": "Agent",
+    "agent_other": "Agents",
     "and": "和",
     "assistant": "智能体",
+    "assistant_one": "助手",
+    "assistant_other": "助手",
     "avatar": "头像",
     "back": "返回",
     "browse": "浏览",

src/renderer/src/pages/home/Tabs/AssistantsTab.tsx

@@ -148,6 +148,7 @@ const Assistants: FC<AssistantsTabProps> = ({
 
   return (
     <Container className="assistants-tab" ref={containerRef}>
+      <span className="mb-2 text-xs text-foreground-400">{t('common.agent_other')}</span>
       <DraggableList
         list={agents}
         onUpdate={setAgents}
@@ -170,6 +171,7 @@ const Assistants: FC<AssistantsTabProps> = ({
         />
       )}
       <Divider className="my-2" />
+      <span className="mb-2 text-xs text-foreground-400">{t('common.assistant_other')}</span>
       <DraggableList
         list={assistants}
         onUpdate={updateAssistants}