fix: 修复配额说明重复和undefined问题

- 在editStorageForm中初始化oss_storage_quota_value和oss_quota_unit
- 删除重复的旧配额说明块，保留新的当前配额设置显示

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

backend/node_modules/lodash.isstring/README.md

@@ -0,0 +1,18 @@
+# lodash.isstring v4.0.1
+
+The [lodash](https://lodash.com/) method `_.isString` exported as a [Node.js](https://nodejs.org/) module.
+
+## Installation
+
+Using npm:
+```bash
+$ {sudo -H} npm i -g npm
+$ npm i --save lodash.isstring
+```
+
+In Node.js:
+```js
+var isString = require('lodash.isstring');
+```
+
+See the [documentation](https://lodash.com/docs#isString) or [package source](https://github.com/lodash/lodash/blob/4.0.1-npm-packages/lodash.isstring) for more details.