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/lazystream/test/data.md

@@ -0,0 +1,13 @@
+> Never mind, hey, this is really exciting, so much to find out about, so much to
+> look forward to, I'm quite dizzy with anticipation . . . Or is it the wind?
+> 
+> There really is a lot of that now, isn't there? And wow! Hey! What's this thing
+> suddenly coming toward me very fast? Very, very fast. So big and flat and round,
+> it needs a big wide-sounding name like . . . ow . . . ound . . . round . . .
+> ground! That's it! That's a good name- ground!
+>
+> I wonder if it will be friends with me?
+>
+> Hello Ground!
+
+And the rest, after a sudden wet thud, was silence.