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/text-decoder/index.js

@@ -0,0 +1,64 @@
+const PassThroughDecoder = require('./lib/pass-through-decoder')
+const UTF8Decoder = require('./lib/utf8-decoder')
+
+module.exports = class TextDecoder {
+  constructor (encoding = 'utf8') {
+    this.encoding = normalizeEncoding(encoding)
+
+    switch (this.encoding) {
+      case 'utf8':
+        this.decoder = new UTF8Decoder()
+        break
+      case 'utf16le':
+      case 'base64':
+        throw new Error('Unsupported encoding: ' + this.encoding)
+      default:
+        this.decoder = new PassThroughDecoder(this.encoding)
+    }
+  }
+
+  get remaining () {
+    return this.decoder.remaining
+  }
+
+  push (data) {
+    if (typeof data === 'string') return data
+    return this.decoder.decode(data)
+  }
+
+  // For Node.js compatibility
+  write (data) {
+    return this.push(data)
+  }
+
+  end (data) {
+    let result = ''
+    if (data) result = this.push(data)
+    result += this.decoder.flush()
+    return result
+  }
+}
+
+function normalizeEncoding (encoding) {
+  encoding = encoding.toLowerCase()
+
+  switch (encoding) {
+    case 'utf8':
+    case 'utf-8':
+      return 'utf8'
+    case 'ucs2':
+    case 'ucs-2':
+    case 'utf16le':
+    case 'utf-16le':
+      return 'utf16le'
+    case 'latin1':
+    case 'binary':
+      return 'latin1'
+    case 'base64':
+    case 'ascii':
+    case 'hex':
+      return encoding
+    default:
+      throw new Error('Unknown encoding: ' + encoding)
+  }
+};