simplify: prune dead code, dedup gmail send, drop neutered log stubs

- Remove no-op log stubs (logGmail, logAutomation, logSecurity, logSystem)
  and ~17 callsites; dead counters in tickets.js and gmail-poll.js go too
- Dedup three near-identical Gmail send paths into sendThreadedEmail helper
- Drop dead Mongoose fields: broccoliniTicketId, lastSyncedBroccoliniArticleId,
  renameCount, renameWindowStart, reminderSent, staffChannelId,
  unclaimedRemindersSent, lastMessageAuthorIsStaff
- Drop dead config fields and their .env.example entries
- Inline api/botClient.js (3-line wrapper, 2 callers)
- Trim unused exports across utils.js, tickets.js, configSchema.js, debugLog.js
- Fix handlers/messages.js to use isStaff() — old partial check ignored
  ADDITIONAL_STAFF_ROLES, so those members were treated as customers
- Drop unused deps p-queue + dotenv-expand; move mongodb to devDependencies

Net: -583 LOC source + -57 LOC lockfile. All 23 modules load clean.

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

db-connection.js

@@ -22,23 +22,16 @@ async function connectMongoDB(uri, options = {}) {
         await mongoose.connect(uri, defaultOptions);
         console.log('✓ Connected to MongoDB');
         
-        // Handle connection events
         mongoose.connection.on('error', (err) => {
             console.error('MongoDB connection error:', err);
-            const { logSystem: ls } = require('./services/debugLog');
-            ls('MongoDB error', [{ name: 'Error', value: err.message }], null, 0xFF0000).catch(() => {});
         });
 
         mongoose.connection.on('disconnected', () => {
             console.warn('MongoDB disconnected. Attempting to reconnect...');
-            const { logSystem: ls } = require('./services/debugLog');
-            ls('MongoDB disconnected', [], null, 0xFFFF00).catch(() => {});
         });
 
         mongoose.connection.on('reconnected', () => {
             console.log('✓ MongoDB reconnected');
-            const { logSystem: ls } = require('./services/debugLog');
-            ls('MongoDB reconnected', []).catch(() => {});
         });
 
     } catch (err) {