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/mimic-response/index.d.ts

@@ -0,0 +1,17 @@
+import {IncomingMessage} from 'http';
+
+/**
+Mimic a [Node.js HTTP response stream](https://nodejs.org/api/http.html#http_class_http_incomingmessage)
+
+Makes `toStream` include the properties from `fromStream`.
+
+@param fromStream - The stream to copy the properties from.
+@param toStream - The stream to copy the properties to.
+@return The same object as `toStream`.
+*/
+declare function mimicResponse<T extends NodeJS.ReadableStream>(
+	fromStream: IncomingMessage, // eslint-disable-line @typescript-eslint/prefer-readonly-parameter-types
+	toStream: T,
+): T & IncomingMessage;
+
+export = mimicResponse;