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/@smithy/util-utf8/dist-es/fromUtf8.js

@@ -0,0 +1,5 @@
+import { fromString } from "@smithy/util-buffer-from";
+export const fromUtf8 = (input) => {
+    const buf = fromString(input, "utf8");
+    return new Uint8Array(buf.buffer, buf.byteOffset, buf.byteLength / Uint8Array.BYTES_PER_ELEMENT);
+};