simplify: rename CONFIG channels, dedup hasStaffRole, drop enforceEmbedLimit

- Rename CONFIG.TRANSCRIPT_CHAN -> CONFIG.TRANSCRIPT_CHANNEL_ID and
  CONFIG.LOG_CHAN -> CONFIG.LOGGING_CHANNEL_ID across 9 callsites so
  CONFIG keys match their .env names — no more "grep .env, find nothing"
  for new readers
- Replace handlers/commands.js#hasStaffRole with utils.js#isStaff
  (was a verbatim copy)
- Delete utils.js#enforceEmbedLimit and its 2 callsites; both inputs are
  bounded well under the 6000-char Discord embed cap, so the trim was
  defensive code that never fired

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

gmail-poll.js

@@ -14,7 +14,6 @@ const {
   stripEmailQuotes,
   stripMobileFooter,
   detectGame,
-  enforceEmbedLimit,
   sanitizeEmbedText
 } = require('./utils');
 const { getGmailClient } = require('./services/gmail');
@@ -225,7 +224,6 @@ async function poll(client) {
             { name: 'Subject', value: `\`\`\`\n${sanitizeEmbedText(subject) || 'No subject'}\n\`\`\``, inline: false }
           );
 
-        enforceEmbedLimit([ticketInfoEmbed]);
         const welcomeMsg = await enqueueSend(ticketChan, {
           content: `<@&${CONFIG.ROLE_ID_TO_PING}>`,
           embeds: [ticketInfoEmbed],
@@ -251,7 +249,7 @@ async function poll(client) {
 
             if (transcriptRows.length > 0) {
               const transcriptChan = await client.channels
-                .fetch(CONFIG.TRANSCRIPT_CHAN)
+                .fetch(CONFIG.TRANSCRIPT_CHANNEL_ID)
                 .catch(() => null);
 
               if (transcriptChan) {