Add per-staff metrics: StaffAction event log + /stats command

Event-sourced tracking of staff/ticket lifecycle actions, plus a /stats
command. Foundation for a future tickets-website analytics dashboard.

Data:
- StaffAction model (event log) + Ticket.game / Ticket.closedAt
- STATS_ADMIN_IDS config (who may view others' stats)

Recording (fire-and-forget, idempotent on real state transitions):
- claim, response (channel reply + /response send), escalate, de-escalate,
  transfer, close (4 sites), reopen — each denormalizes ticketType, tier,
  priority, game, requester (senderEmail / creatorId), guildId
- close events carry closerType / resolverId (claimer credit) / wasClaimed;
  transfer carries fromId / toId; reopen stamps resolverId
- conditional close transition helper (atomic open->closed + closedAt) shared
  by all four close paths

Query + command:
- pure period parser (presets + free-text) and stats shaper (per-metric keys)
- command-aware autocomplete dispatch
- /stats: period (autocomplete) + member (admin-gated) + source (all/email/
  discord), ManageMessages + staff-role gated, ephemeral, tier-labeled embed

288+ unit tests; timing/busiest-times data is collected but displayed later.

handlers/buttons.js

@@ -22,12 +22,13 @@ const {
 } = require('discord.js');
 const { mongoose } = require('../db-connection');
 const { CONFIG } = require('../config');
-const { makeTicketName, resolveCreatorNickname, getOrCreateTicketCategory, cleanupEmptyOverflowCategory, checkTicketCreationRateLimit, toDiscordSafeName } = require('../services/tickets');
+const { makeTicketName, resolveCreatorNickname, getOrCreateTicketCategory, cleanupEmptyOverflowCategory, checkTicketCreationRateLimit, toDiscordSafeName, attemptCloseTransition } = 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');
+const { sanitizeEmbedText, truncateEmbedDescription, isStaff } = require('../utils');
+const { recordAction } = require('../services/staffStats');
 const { enqueueRename, enqueueSend } = require('../services/channelQueue');
 const { runEscalation, runDeescalation, resolveEscalationCategoryId } = require('./commands');
 const { pendingCloses } = require('./pendingCloses');
@@ -158,14 +159,24 @@ async function handleClaimButton(interaction, ticket) {
   }
 }
 
-async function applyClaim(interaction, freshTicket, row, btnClose, btnClaim, claimerLabel, guild) {
-  await Ticket.updateOne(
-    { gmailThreadId: freshTicket.gmailThreadId },
+async function applyClaim(interaction, freshTicket, row, btnClose, btnClaim, claimerLabel, guild, _TicketModel, _recordAction) {
+  const T = _TicketModel || Ticket;
+  const record = _recordAction || recordAction;
+
+  const result = await T.updateOne(
+    { gmailThreadId: freshTicket.gmailThreadId, claimerId: { $ne: interaction.user.id } },
     { $set: { claimedBy: claimerLabel, claimerId: interaction.user.id } }
   );
   freshTicket.claimedBy = claimerLabel;
   freshTicket.claimerId = interaction.user.id;
 
+  if (result.modifiedCount === 1) {
+    record(interaction.user.id, 'claim', {
+      ticket: freshTicket,
+      guildId: interaction.guild?.id
+    });
+  }
+
   const claimerEmoji = CONFIG.STAFF_EMOJIS[interaction.user.id] || CONFIG.CLAIMER_EMOJI_FALLBACK;
   const creatorNickname = await resolveCreatorNickname(guild, freshTicket);
   const state = freshTicket.escalated ? 'escalated-claimed' : 'claimed';
@@ -442,12 +453,17 @@ async function runFinalClose(interaction, ticket, sendEmail = true) {
       await sendTicketClosedEmail(ticket, closerDisplayName, interaction.user.id);
     }
 
-    // $unset welcomeMessageId so a future reopen on this thread doesn't carry
-    // a stale message ID pointing into the now-deleted channel.
-    await Ticket.updateOne(
-      { gmailThreadId: ticket.gmailThreadId },
-      { $set: { discordThreadId: null, status: 'closed' }, $unset: { welcomeMessageId: '' } }
-    );
+    const { transitioned, ticket: closedTicket } = await attemptCloseTransition(ticket.gmailThreadId, { discordThreadId: null }, { welcomeMessageId: '' });
+    if (transitioned) {
+      const closerType = isStaff(interaction.member) ? 'staff' : 'user';
+      recordAction(interaction.user.id, 'close', {
+        ticket: closedTicket,
+        guildId: interaction.guild?.id,
+        closerType,
+        resolverId: closedTicket.claimerId ?? null,
+        wasClaimed: Boolean(closedTicket.claimerId)
+      });
+    }
 
     // File the email thread into the Resolved folder — non-fatal, email tickets only.
     if (!ticket.gmailThreadId?.startsWith('discord-')) {
@@ -754,4 +770,4 @@ async function handleButton(interaction) {
   return ticketHandler(interaction, ticket);
 }
 
-module.exports = { handleButton, handleTicketModal };
+module.exports = { handleButton, handleTicketModal, runFinalClose, applyClaim };