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/toUtf8.browser.js

@@ -0,0 +1,9 @@
+export const toUtf8 = (input) => {
+    if (typeof input === "string") {
+        return input;
+    }
+    if (typeof input !== "object" || typeof input.byteOffset !== "number" || typeof input.byteLength !== "number") {
+        throw new Error("@smithy/util-utf8: toUtf8 encoder function only accepts string | Uint8Array.");
+    }
+    return new TextDecoder("utf-8").decode(input);
+};