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

services/configSchema.js

@@ -24,23 +24,22 @@ const ALLOWED_CONFIG_KEYS = new Set([
   'EMAIL_ESCALATED2_CHANNEL_ID', 'DISCORD_ESCALATED2_CHANNEL_ID',
   'EMAIL_ESCALATED3_CHANNEL_ID', 'DISCORD_ESCALATED3_CHANNEL_ID',
   // Roles and staff
-  'ROLE_ID_TO_PING', 'ROLE_TO_PING_ID', 'ADDITIONAL_STAFF_ROLES', 'BLACKLISTED_ROLES',
+  'ROLE_ID_TO_PING', 'ADDITIONAL_STAFF_ROLES', 'BLACKLISTED_ROLES',
   'ADMIN_ID',
   // Channel IDs
   'TRANSCRIPT_CHANNEL_ID', 'LOGGING_CHANNEL_ID', 'DEBUGGING_CHANNEL_ID',
-  'RENAME_LOG_CHANNEL_ID',
   // Messages and labels
   'ESCALATION_MESSAGE', 'TICKET_CLOSE_SUBJECT_PREFIX', 'TICKET_CLOSE_MESSAGE', 'TICKET_CLOSE_SIGNATURE',
   'DISCORD_CLOSE_MESSAGE', 'DISCORD_TRANSCRIPT_MESSAGE', 'DISCORD_AUTO_CLOSE_MESSAGE',
   'TICKET_WELCOME_MESSAGE', 'TICKET_CLAIMED_MESSAGE', 'TICKET_UNCLAIMED_MESSAGE',
-  'REMINDER_MESSAGE', 'BUTTON_LABEL_CLOSE', 'BUTTON_LABEL_CLAIM', 'BUTTON_LABEL_UNCLAIM',
+  'BUTTON_LABEL_CLOSE', 'BUTTON_LABEL_CLAIM', 'BUTTON_LABEL_UNCLAIM',
   'BUTTON_EMOJI_CLOSE', 'BUTTON_EMOJI_CLAIM', 'BUTTON_EMOJI_UNCLAIM',
   // Branding
   'LOGO_URL', 'SUPPORT_NAME', 'EMAIL_SIGNATURE', 'GAME_LIST',
   // Toggles
   'AUTO_CLOSE_ENABLED', 'AUTO_CLOSE_AFTER_HOURS', 'AUTO_UNCLAIM_ENABLED', 'AUTO_UNCLAIM_AFTER_HOURS',
   'ALLOW_CLAIM_OVERWRITE',
-  'REMINDER_ENABLED', 'REMINDER_AFTER_HOURS', 'PRIORITY_ENABLED', 'DEFAULT_PRIORITY',
+  'PRIORITY_ENABLED', 'DEFAULT_PRIORITY',
   'STAFF_THREAD_ENABLED', 'STAFF_THREAD_NAME', 'STAFF_THREAD_AUTO_ADD_ROLE', 'STAFF_THREAD_ROLE_ID',
   'PIN_INITIAL_MESSAGE_ENABLED', 'PIN_ESCALATION_MESSAGE_ENABLED', 'PIN_SUPPRESS_SYSTEM_MESSAGE',
   // Limits and thresholds
@@ -140,26 +139,6 @@ const VALIDATORS = {
       return { ok: true, coerced: parts.join(',') };
     }
   },
-  json: {
-    type: 'json',
-    validate(value) {
-      if (isEmptyInput(value)) return { ok: true, coerced: '' };
-      const str = String(value);
-      try {
-        JSON.parse(str);
-        return { ok: true, coerced: str };
-      } catch (_) {
-        return { ok: false, error: 'must be valid JSON' };
-      }
-    }
-  },
-  string_or_json: {
-    type: 'string_or_json',
-    validate(value) {
-      if (value === null || value === undefined) return { ok: false, error: 'cannot be null' };
-      return { ok: true, coerced: String(value) };
-    }
-  },
   // Fallback. Preserves legacy coercion so CONFIG.* values keep their types
   // for consumers that compare with === true / === 5 (see old applyConfigUpdates).
   string: {