Mail: folder unread counts refresh at once after a change, read state survives a late list, no wrong message after quick clicks, mark unread keeps the message in the list

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

mail.js

@@ -155,7 +155,7 @@ const safeName = n => String(n || 'attachment').replace(/[\r\n"\\/]+/g, '_').sli
 const cleanAttachments = list => { let total = 0; const out = (Array.isArray(list) ? list : []).slice(0, 10).map(a => { const data = String(a.data || ''); total += Buffer.from(data, 'base64').length; return { name: safeName(a.name), type: String(a.type || 'application/octet-stream').slice(0, 100), data }; }); if (total > MAX_ATTACH) throw fail(400, 'Attachments can total about 3 MB'); return out; };
 
 let folderCache = new Map(); // account id -> { t, v }
-const dropFolderCache = id => { if (id) { folderCache.delete(id); unreadCache.delete(id); } else { folderCache.clear(); unreadCache.clear(); } };
+const dropFolderCache = id => { if (id) { folderCache.delete(id); unreadCache.delete(id); } else { folderCache.clear(); unreadCache.clear(); } imap.dropFolders(id); };
 
 // ---- Outlook.com through Microsoft Graph. Every function takes the account and Graph's own ids.
 const outlook = {