Email ticketing fixes, comms polish, and .env cleanup

Inbound:
- Gmail poll query is:unread in:inbox (was category:primary, which matched
  nothing on a no-tabs Workspace inbox)

Outbound email:
- Closed/escalation auto-emails editable via TICKET_CLOSE_MESSAGE and new
  TICKET_ESCALATION_EMAIL_MESSAGE; drop the staff signature from closing emails
- Replies quote the customer's latest message (gmail_quote markup so clients
  collapse it), embed custom emoji inline via CID attachment, and strip Discord
  role mentions
- Tagline spacing fix in the company signature

Discord side:
- Suppress all mentions in log + transcript posts (no more pinging on close)
- Drop the staff-role ping from new-ticket and follow-up notifications
- Ticket channels inherit category permissions instead of setting per-channel
  overwrites (removes the Manage Roles requirement)

Gmail folders:
- Folder/label routing (gmailLabels.js) with /folder; close files to Complete

Config:
- Remove ~56 stale .env keys for long-removed features; refresh stale copy

Docs:
- Design specs for folder routing, email-flow toggle, and per-staff metrics

broccolini-discord.js

@@ -207,8 +207,12 @@ client.once('ready', async () => {
 
   registerCommands().catch(console.error);
 
-  gmailPollInterval = trackInterval(setInterval(() => poll(client), CONFIG.GMAIL_POLL_INTERVAL_MS));
-  poll(client);
+  if (CONFIG.GMAIL_POLL_ENABLED) {
+    gmailPollInterval = trackInterval(setInterval(() => poll(client), CONFIG.GMAIL_POLL_INTERVAL_MS));
+    poll(client);
+  } else {
+    console.log('Gmail poll disabled by config (GMAIL_POLL_ENABLED=false) — inbox will not be polled. Enable with /email on.');
+  }
 
   if (CONFIG.AUTO_CLOSE_ENABLED) {
     trackInterval(setInterval(() => checkAutoClose(client, sendTicketClosedEmail), 60 * 60 * 1000));