feat: implement drag-and-drop sorting for knowledge directories and add localization for sort actions

web/messages/en-US.json

@@ -1804,6 +1804,8 @@
     "directoryDeleted": "Directory deleted: {name}",
     "directorySaveFailed": "Could not save the directory.",
     "directoryDeleteFailed": "Could not delete the directory.",
+    "directorySortUpdated": "Directory order updated.",
+    "directorySortUpdateFailed": "Could not update directory order.",
     "directoryNameRequired": "Directory name is required.",
     "rebuildStarted": "Knowledge base reindex started: {name}",
     "rebuildFailed": "Could not rebuild the knowledge base index.",

web/messages/zh-CN.json

@@ -1804,6 +1804,8 @@
     "directoryDeleted": "已删除目录：{name}",
     "directorySaveFailed": "保存目录失败",
     "directoryDeleteFailed": "删除目录失败",
+    "directorySortUpdated": "目录排序已更新",
+    "directorySortUpdateFailed": "更新目录排序失败",
     "directoryNameRequired": "目录名称不能为空",
     "rebuildStarted": "已开始重建知识库索引：{name}",
     "rebuildFailed": "重建知识库索引失败",