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/mime/cli.js

@@ -0,0 +1,8 @@
+#!/usr/bin/env node
+
+var mime = require('./mime.js');
+var file = process.argv[2];
+var type = mime.lookup(file);
+
+process.stdout.write(type + '\n');
+