fix: address code quality issues in session pool, approval, and main

- session.ts: add onReconnect callback so reconnected socket replaces stale pool entry
- session-pool.ts: pass onReconnect to update pool on reconnect; add closeAll() to gracefully end WebSocket connections on shutdown
- approval.ts: use approved flag so double-approval race (updateMany count=0) returns null instead of sending duplicate forward jobs
- main.ts: wrap pool.add() in try/catch to continue if one account fails; replace silent groupMap fallback with explicit error log and early return; call pool.closeAll() before BullMQ shutdown to prevent hanging sockets
- Tests: add closeAll() test to session-pool.test.ts; add double-approval race test to approval.test.ts (56 tests total, all passing)

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

apps/worker/src/main.ts

@@ -48,6 +48,7 @@ async function bootstrap() {
   for (const account of accounts) {
     groupMaps.set(account.id, new Map());
 
+    try {
     await pool.add(
       account.id,
       account.sessionPath,
@@ -55,7 +56,11 @@ async function bootstrap() {
         const tags = detectTags(msg.content, msg.senderJid, adminJids);
         if (!isFlagged(tags)) return;
 
-        const groupMap = groupMaps.get(accountId) ?? new Map();
+        const groupMap = groupMaps.get(accountId);
+        if (!groupMap) {
+          logger.error({ accountId }, 'No group map for account — message dropped');
+          return;
+        }
         const sourceGroupId = groupMap.get(msg.sourceGroupJid);
         if (!sourceGroupId) {
           logger.warn({ jid: msg.sourceGroupJid, accountId }, 'Unknown group — skipping message');
@@ -101,12 +106,16 @@ async function bootstrap() {
         groupMaps.set(accountId, map);
       },
     );
+    } catch (err) {
+      logger.error({ accountId: account.id, err }, 'Failed to start session — skipping account');
+    }
   }
 
   logger.info({ accountCount: accounts.length }, 'Tower worker ready');
 
   const shutdown = async () => {
     logger.info('Shutting down...');
+    await pool.closeAll();
     await ingestWorker.close();
     await forwardWorker.close();
     await ingestQueue.close();