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/core/approval.test.ts

@@ -76,6 +76,29 @@ describe('handleStarReaction', () => {
     expect(await handleStarReaction(makeReaction(), adminJids, prisma)).toBeNull();
   });
 
+  it('returns null on double-approval race (updateMany returns count=0)', async () => {
+    const prisma = {
+      message: {
+        findUnique: jest.fn().mockResolvedValue({
+          id: 'msg_1',
+          status: 'PENDING',
+          approval: null,
+          content: 'hello',
+          senderName: 'Alice',
+          sourceGroup: { name: 'UP Parivar Dallas', syncRoutesFrom: [] },
+        }),
+      },
+      $transaction: jest.fn().mockImplementation(async (fn: any) => fn({
+        message: { updateMany: jest.fn().mockResolvedValue({ count: 0 }) },
+        approval: { create: jest.fn().mockResolvedValue({}) },
+      })),
+    } as any;
+
+    const result = await handleStarReaction(makeReaction(), adminJids, prisma);
+    expect(result).toBeNull();
+    expect(prisma.$transaction).toHaveBeenCalled();
+  });
+
   it('approves message and returns empty array when no sync routes', async () => {
     const prisma = {
       message: {