feat(frontend): 增强连接树悬停操作与拖拽占位反馈

为连接管理页左侧标签树增加悬停工具按钮，
补充分隔标题行与节点拖拽目标高亮提示。

同时同步多语言文案与 helloagents 归档记录，
为后续真实重排交互预留可见反馈入口

packages/frontend/src/locales/en-US.json

@@ -369,6 +369,9 @@
     "scopeTreeSearch": "Search tag tree...",
     "scopeSearchMode": "Matched paths are expanded",
     "scopeTreeNoMatch": "No matching tree nodes",
+    "scopeDragPlaceholder": "Drag-reorder is reserved for now; only target placeholder feedback is shown.",
+    "scopePinAction": "Focus this scope",
+    "scopeDragAction": "Drag to reorder (reserved)",
     "untaggedGroup": "Untagged",
     "noUntaggedConnections": "No untagged connections found."
   },

packages/frontend/src/locales/ja-JP.json

@@ -273,6 +273,9 @@
         "scopeTreeSearch": "タグツリーを検索...",
         "scopeSearchMode": "一致したパスを自動展開中",
         "scopeTreeNoMatch": "一致するツリーノードはありません",
+        "scopeDragPlaceholder": "ドラッグ並べ替えは予約中で、現在は配置先のプレースホルダーのみ表示します。",
+        "scopePinAction": "この範囲にフォーカス",
+        "scopeDragAction": "ドラッグで並べ替え（予約）",
         "table": {
             "actions": "アクション",
             "authMethod": "認証方法",

packages/frontend/src/locales/zh-CN.json

@@ -369,6 +369,9 @@
     "scopeTreeSearch": "搜索标签树...",
     "scopeSearchMode": "命中路径已自动展开",
     "scopeTreeNoMatch": "没有匹配的树节点",
+    "scopeDragPlaceholder": "拖拽排序预留中，当前仅展示目标占位反馈。",
+    "scopePinAction": "定位到此范围",
+    "scopeDragAction": "拖拽重排（预留）",
     "untaggedGroup": "未标记",
     "noUntaggedConnections": "没有未标记的连接。"
   },