Final integration testing

[copyleftdev]

Depends on: #44, #45

Final MVP validation:

• Integration: Full 3-node cluster with clients
• Integration: Multi-room concurrent usage
• Chaos: Random faults during operation
• Soak: 24-hour continuous operation

Acceptance:

• All integration tests pass
• 24-hour soak: zero crashes
• No memory leaks
• Performance targets maintained