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/@aws-crypto/sha256-browser/README.md

@@ -0,0 +1,31 @@
+# @aws-crypto/sha256-browser
+
+SHA256 wrapper for browsers that prefers `window.crypto.subtle` but will
+fall back to a pure JS implementation in @aws-crypto/sha256-js
+to provide a consistent interface for SHA256.
+
+## Usage
+
+- To hash "some data"
+```
+import {Sha256} from '@aws-crypto/sha256-browser'
+
+const hash = new Sha256();
+hash.update('some data');
+const result = await hash.digest();
+
+```
+
+- To hmac "some data" with "a key"
+```
+import {Sha256} from '@aws-crypto/sha256-browser'
+
+const hash = new Sha256('a key');
+hash.update('some data');
+const result = await hash.digest();
+
+```
+
+## Test
+
+`npm test`