Remove dead/stale code, dedup close+escalation paths

Dead/stale removals (grep-confirmed no consumers):
- config: drop 9 unread CONFIG keys (ROLE_TO_PING_ID, SIGNATURE,
  REMINDER_*, RENAME_LOG_CHANNEL_ID, SETTINGS_*); remove their
  ALLOWED_CONFIG_KEYS entries and the orphaned settings-site UI fields
- configSchema: delete unreachable json/string_or_json validators
- models: drop unused ticketTag field
- gmail-poll: remove unused isPollSuspended export
- utils: remove dead htmlToTextWithBlocks/decodeHtmlEntities/BLOCK_TAG_REGEX
- internalApi: remove router._allowedKeys (test it served is gone)
- discord client: drop unused GuildPresences privileged intent
- broccolini-discord: remove dormant /api 503 gate (no /api routes)

Fixes:
- context-menu ticket create now uses makeTicketName('unclaimed', ...)
  instead of the contract-violating ticket-<n> name
- drop write-only pending.userId from both close paths

Dedup / simplify:
- new services/transcript.js shares the transcript text/date/header
  builders between the button and force-close paths (had drifted)
- resolveEscalationCategoryId() replaces 3 copies of the category logic
- ticketChannelOverwrites() shares the create-permission array between
  the two interactive ticket-create paths
- finalizeBody() shares the email-cleanup tail in parseGmailMessage
- getTicketActionRow drops its never-passed options arg;
  sendTicketNotificationEmail drops its always-null subjectLine arg
- hoist invariant guild lookup out of the auto-close/unclaim loops
- drop redundant lastActivity write (and now-dead updateTicketActivity)
- /help lists all current commands and the right-click apps

settings-site/public/index.html

@@ -84,7 +84,6 @@
         <div class="field"><label>Debugging Channel</label><input type="text" data-key="DEBUGGING_CHANNEL_ID" data-smart="channel"></div>
         <div class="field"><label>Gmail Log Channel</label><input type="text" data-key="GMAIL_LOG_CHANNEL_ID" data-smart="channel"></div>
         <div class="field"><label>Automation Log Channel</label><input type="text" data-key="AUTOMATION_LOG_CHANNEL_ID" data-smart="channel"></div>
-        <div class="field"><label>Rename Log Channel</label><input type="text" data-key="RENAME_LOG_CHANNEL_ID" data-smart="channel"></div>
         <div class="field"><label>Security Log Channel</label><input type="text" data-key="SECURITY_LOG_CHANNEL_ID" data-smart="channel"></div>
         <div class="field"><label>System Log Channel</label><input type="text" data-key="SYSTEM_LOG_CHANNEL_ID" data-smart="channel"></div>
       </div></div>
@@ -123,8 +122,6 @@
       <div class="section-body"><div class="field-grid">
         <div class="field"><label>Auto-Close</label><div class="toggle-wrap"><label class="toggle"><input type="checkbox" data-key="AUTO_CLOSE_ENABLED"><span class="slider"></span></label><span>Enabled</span></div></div>
         <div class="field"><label>Auto-Close Hours</label><input type="number" data-key="AUTO_CLOSE_AFTER_HOURS"></div>
-        <div class="field"><label>Reminders</label><div class="toggle-wrap"><label class="toggle"><input type="checkbox" data-key="REMINDER_ENABLED"><span class="slider"></span></label><span>Enabled</span></div></div>
-        <div class="field"><label>Reminder Hours</label><input type="number" data-key="REMINDER_AFTER_HOURS"></div>
         <div class="field"><label>Auto-Unclaim</label><div class="toggle-wrap"><label class="toggle"><input type="checkbox" data-key="AUTO_UNCLAIM_ENABLED"><span class="slider"></span></label><span>Enabled</span></div></div>
         <div class="field"><label>Auto-Unclaim Hours</label><input type="number" data-key="AUTO_UNCLAIM_AFTER_HOURS"></div>
         <div class="field"><label>Allow Claim Overwrite</label><div class="toggle-wrap"><label class="toggle"><input type="checkbox" data-key="ALLOW_CLAIM_OVERWRITE"><span class="slider"></span></label><span>Enabled</span></div></div>
@@ -136,7 +133,6 @@
         <div class="field full-width"><label>Claimed Message</label><textarea data-key="TICKET_CLAIMED_MESSAGE" rows="2"></textarea><div class="hint">Variables: {staff_mention}, {staff_name}</div></div>
         <div class="field full-width"><label>Unclaimed Message</label><textarea data-key="TICKET_UNCLAIMED_MESSAGE" rows="2"></textarea></div>
         <div class="field full-width"><label>Escalation Message</label><textarea data-key="ESCALATION_MESSAGE" rows="3"></textarea><div class="hint">Variables: {support_name}</div></div>
-        <div class="field full-width"><label>Reminder Message</label><textarea data-key="REMINDER_MESSAGE" rows="2"></textarea><div class="hint">Variables: {ping}, {hours}</div></div>
       </div></div>
     </div>