fix: correct Produce v7 request parsing for Sarama compatibility
✅ MAJOR FIX: Produce v7 Request Parsing
- Fixed client_id, transactional_id, acks, timeout parsing
- Now correctly parses Sarama requests:
* client_id: sarama ✅
* transactional_id: null ✅
* acks: -1, timeout: 10000 ✅
* topics count: 1 ✅
* topic: sarama-e2e-topic ✅
🔧 NEXT: Fix Produce v7 response format
- Sarama getting 'invalid length' error on response
- Response parsing issue, not request parsing