feat(sync): 添加 Vault 所有的用户 Skill 记录

docs/contracts/后端接口契约-开发版.md

@@ -72,6 +72,11 @@ Web 联调阶段只暴露后端通过 `APP_VAULT_PATH` 配置的单一 Vault，
 | POST | `/api/skills/{skill_id}/enable` | 启用 Skill |
 | POST | `/api/skills/{skill_id}/disable` | 停用 Skill |
 | DELETE | `/api/skills/{skill_id}` | 卸载 Skill |
+| GET | `/api/user-skills` | 列出当前 Vault 的用户 Skill 逻辑记录 |
+| POST | `/api/user-skills` | 新建用户 Skill；支持 UUID Idempotency-Key |
+| GET | `/api/user-skills/{skill_id}` | 读取用户 Skill 与内容 revision |
+| PUT | `/api/user-skills/{skill_id}` | 以内容 revision CAS 更新用户 Skill |
+| DELETE | `/api/user-skills/{skill_id}?revision=...` | 以内容 revision CAS 删除用户 Skill |
 | GET | `/api/plugins` | 获取 Plugin 列表及状态 |
 | POST | `/api/plugins/install` | 安装 Plugin |
 | GET | `/api/plugins/{plugin_id}` | 获取 Plugin Manifest 与状态 |