docs(research): add Peer Review Response template (#415)

Complete template for academic conference rebuttals:
- 8 response templates by concern type
- Tone guidelines (DO's and DON'Ts)
- Conference-specific guidelines (NeurIPS, ICLR, MLSys, AAAI)
- Example complete response included
- Response checklist for quality assurance

~1,500 LOC

Author: Antigravity Agent