fix(skills): preserve SKILL.md content when renaming

Rename skills by moving the skill directory and updating frontmatter
name instead of recreate-with-stub-description, which wiped the body
and supporting files.

Co-authored-by: Serhii Dziupin <makeittech@users.noreply.github.com>

packages/ui/src/lib/i18n/messages/ja.settings.ts

@@ -721,6 +721,7 @@ export const settingsDict = {
   'settings.skills.sidebar.toast.renameLoadFailed': 'Skill 詳細の読み込みに失敗しました',
   'settings.skills.sidebar.toast.removeOldAfterRenameFailed': '名前変更後に古い Skill の削除に失敗しました',
   'settings.skills.sidebar.toast.renameFailed': 'Skill の名前変更に失敗しました',
+  'settings.skills.sidebar.toast.skillRenamed': 'Skill の名前を「{name}」に変更しました',
   'settings.skills.sidebar.deleteDialog.title': 'Skill を削除',
   'settings.skills.sidebar.deleteDialog.description': 'Skill "{name}" を削除してもよろしいですか？',
   'settings.skills.sidebar.renameDialog.title': 'Skill の名前変更',