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

handlers/buttons.js

@@ -24,6 +24,7 @@ const { mongoose } = require('../db-connection');
 const { CONFIG } = require('../config');
 const { makeTicketName, resolveCreatorNickname, getOrCreateTicketCategory, cleanupEmptyOverflowCategory, checkTicketCreationRateLimit, toDiscordSafeName } = require('../services/tickets');
 const { sendTicketClosedEmail } = require('../services/gmail');
+const { moveThreadToFolder } = require('../services/gmailLabels');
 const { getTicketActionRow, ticketChannelOverwrites } = require('../utils/ticketComponents');
 const { buildTranscriptText, formatDateForTranscript, renderTranscriptHeader } = require('../services/transcript');
 const { sanitizeEmbedText, truncateEmbedDescription } = require('../utils');
@@ -422,7 +423,8 @@ async function runFinalClose(interaction, ticket, sendEmail = true) {
     if (transcriptChan) {
       transcriptMsg = await enqueueSend(transcriptChan, {
         content: transcriptContent,
-        files: [file]
+        files: [file],
+        allowedMentions: { parse: [] }
       });
     }
 
@@ -447,6 +449,12 @@ async function runFinalClose(interaction, ticket, sendEmail = true) {
       { $set: { discordThreadId: null, status: 'closed' }, $unset: { welcomeMessageId: '' } }
     );
 
+    // File the email thread into the Resolved folder — non-fatal, email tickets only.
+    if (!ticket.gmailThreadId?.startsWith('discord-')) {
+      moveThreadToFolder(ticket.gmailThreadId, 'RESOLVED')
+        .catch(err => logError('gmailLabels: resolved move', err).catch(() => {}));
+    }
+
     if (transcriptMsg?.id) {
       await Transcript.create({
         gmailThreadId: ticket.gmailThreadId,
@@ -519,7 +527,7 @@ async function postCloseLogEntry(interaction, ticket, channelName) {
   } else {
     logMsg = `Closed **${channelName}** (${ticket.senderEmail}) by ${closerMention} (${closerDisplayName})`;
   }
-  await enqueueSend(logChan, logMsg);
+  await enqueueSend(logChan, { content: logMsg, allowedMentions: { parse: [] } });
 }
 
 // ============================================================
@@ -607,7 +615,7 @@ async function handleTicketModal(interaction) {
     if (CONFIG.LOGGING_CHANNEL_ID) {
       const logChan = await interaction.client.channels.fetch(CONFIG.LOGGING_CHANNEL_ID).catch(() => null);
       if (logChan) {
-        await enqueueSend(logChan, `📝 ${channel.name} created by ${interaction.user.tag}`);
+        await enqueueSend(logChan, { content: `📝 ${channel.name} created by ${interaction.user.tag}`, allowedMentions: { parse: [] } });
       }
     }
   } catch (err) {