Mail: instant first paint from the last saved accounts, folders and list; Outlook folders in one batched call; gzip for app files and large mail responses

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

tools/mail-imap-test.js

@@ -56,7 +56,9 @@ const free = () => 21000 + Math.floor(Math.random() * 20000);
   r = await A('/api/mail/status'); ok('status lists the account with its unread count (2 unread in the inbox)', r.json.connected && r.json.accounts.length === 1 && r.json.accounts[0].unread === 2 && r.json.unread === 2, r.json);
 
   r = await A('/api/mail/status?light=1'); ok('the light status lists the accounts without asking the mail servers (what lets the Mail tab draw at once)', r.json.connected && r.json.accounts.length === 1 && !r.json.accounts[0].error, r.json);
-  const t0 = Date.now(); r = await A('/api/mail/status'); const t1 = Date.now(); r = await A('/api/mail/status'); ok('the full status is answered from a short-lived cache the second time (counts are refreshed at most every 30 s)', Date.now() - t1 <= Math.max(50, t1 - t0), [t1 - t0, Date.now() - t1]);
+  { const first = (await A('/api/mail/status')).json.unread; // unread counts are cached for 30 s: change the real mailbox behind the hub's back and the number stays
+    const c = new ImapFlow({ host: '127.0.0.1', port: imapPort, secure: false, doSTARTTLS: false, auth: { user: ME, pass: PASS }, logger: false }); await c.connect(); const lock = await c.getMailboxLock('INBOX');
+    try { await c.messageFlagsAdd('1', ['\\Seen']); const again = (await A('/api/mail/status')).json.unread; ok('the full status serves a cached unread count for up to 30 s (so opening Mail never waits on the mail servers)', again === first, [first, again]); await c.messageFlagsRemove('1', ['\\Seen']); } finally { lock.release(); await c.logout(); } }
 
   // ================= reading =================
   r = await A('/api/mail/folders?acct=' + gm.id); const names = r.json.map(f => f.name);