docs: update HANDOFF.md with session 02 summary

- Add session entry for PR #89 protocol enhancement and merge resolution
- Update status to reflect merge conflicts resolved
- Document PR #199 (protocol updates) and Issue #198 (Merge Resolver agent)
- Include cumulative reviewer signal quality metrics

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

Author: rjmurillo-bot

.agents/HANDOFF.md

@@ -4,7 +4,7 @@
 **Version**: 1.0
 **Last Updated**: 2025-12-20
 **Current Phase**: PR #89 Cross-Repo Issue Linking
-**Status**: ✅ All review comments addressed, ready for merge
+**Status**: ✅ Merge conflicts resolved, PR ready for review
 
 ---
 
@@ -546,6 +546,53 @@ Both threads received additional verification replies at 10:58 (3 hours after re
 
 ---
 
+### 2025-12-20: PR #89 Protocol Enhancement & Merge Conflict Resolution (Session 02)
+
+**Objective**: Enhance pr-comment-responder protocol with mandatory memory phases, resolve merge conflicts, and separate protocol updates into dedicated PR.
+
+**Agent**: orchestrator (Claude Opus 4.5)
+
+**Branch**: `copilot/fix-cross-repo-issue-linking`
+
+**PRs**:
+- [#89](https://github.com/rjmurillo/ai-agents/pull/89) - Main fix (merge conflicts resolved)
+- [#199](https://github.com/rjmurillo/ai-agents/pull/199) - Protocol updates (split from #89)
+
+**Issues Created**:
+- [#198](https://github.com/rjmurillo/ai-agents/issues/198) - New Agent: Merge Resolver for intelligent git conflict resolution
+
+**Outcome**: SUCCESS
+
+**Work Completed**:
+
+1. **Protocol Enhancement** (PR #199):
+   - Added Phase 0 (Memory Initialization) - BLOCKING gate before triage
+   - Added Phase 9 (Memory Storage) - REQUIRED before workflow completion
+   - Updated cumulative performance table from PR #52 to PR #89
+   - Updated `.serena/memories/pr-comment-responder-skills.md` with PR #89 stats
+
+2. **Merge Conflict Resolution** (PR #89):
+   - Resolved 2 conflicts in `.agents/HANDOFF.md`
+   - Combined session entries from both branches
+   - Preserved all session history
+
+3. **Merge Resolver Agent Concept** (Issue #198):
+   - Created comprehensive GitHub issue for new agent
+   - Defined core capabilities, workflow, and resolution heuristics
+   - Included success criteria and integration points
+
+**Reviewer Signal Quality (as of PR #89)**:
+
+| Reviewer | PRs | Comments | Actionable | Signal |
+|----------|-----|----------|------------|--------|
+| cursor[bot] | 4 | 11 | 11 | **100%** |
+| Copilot | 4 | 12 | 7 | **58%** |
+| coderabbitai | 2 | 6 | 3 | **50%** |
+
+**Status**: Complete
+
+---
+
 ### 2025-12-20: Get-PRContext.ps1 Syntax Error Fix (Session 36)
 
 **Session Log**: `.agents/retrospective/2025-12-20-get-prcontext-syntax-error.md`