chore: Add Phase 2-3 validation templates for Gate 5 roadmap execution

Phase 2: PBO/DSR Metrics Validation
- Template for collecting Probability of Backtest Overfit metrics
- DSR (Daily Sharpe Ratio) validation checklist
- OOS (Out-of-Sample) performance by market phase
- Pass/fail criteria for each metric
- Evidence collection and archiving plan

Phase 3: Crash Recovery Rehearsal
- Four failure scenarios: outbox loss, DB drop, lock timeout, inbox failure
- Recovery procedures: state reconciliation, message replay, lock recovery
- Test result tracking matrix
- Verification checklist for each procedure
- Evidence documentation

Status (2026-08-03 22:30 KST):
✅ Phase 1 (Job 893): RUNNING (22:04 KST start)
✅ Phase 2 template: READY
✅ Phase 3 template: READY
⏳ Phase 4 template: NEXT

These templates enable systematic Phase 2-3 execution when Phase 1 completes.

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

metrics/pbo_dsr_validation.md

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+# Gate 5: PBO/DSR Metrics Validation Report
+
+**Status:** ⏳ IN PREPARATION  
+**Phase:** 2 (Post Job 893 Execution)  
+**Timeline:** TBD (5-10 days after Phase 1)  
+**Template Version:** 2026-08-03
+
+---
+
+## 📊 **Metrics Summary**
+
+### PBO (Probability of Backtest Overfit)
+| Metric | Target | Result | Status |
+|--------|--------|--------|--------|
+| **PBO Value** | ≥ ? | TBD | ⏳ Pending |
+| **CSCV Score** | ≥ ? | TBD | ⏳ Pending |
+| **Confidence Interval** | 95% | TBD | ⏳ Pending |
+| **Sample Size** | 252+ days | TBD | ⏳ Pending |
+
+### DSR (Daily Sharpe Ratio)
+| Metric | Target | Result | Status |
+|--------|--------|--------|--------|
+| **DSR Value** | > baseline | TBD | ⏳ Pending |
+| **Baseline** | ? | TBD | ⏳ Pending |
+| **Minimum Period** | 252 days | TBD | ⏳ Pending |
+| **Volatility** | Acceptable | TBD | ⏳ Pending |
+
+---
+
+## ✅ **Validation Checklist**
+
+### PBO Validation
+- [ ] Data extracted from Job 893
+- [ ] CSCV methodology applied (or simplified variant if DEBT-009 deferred)
+- [ ] Cross-validation performed
+- [ ] Confidence intervals calculated
+- [ ] Results within acceptable range
+- [ ] Evidence documented
+
+### DSR Validation
+- [ ] Daily returns calculated
+- [ ] Sharpe ratio computed (252-day window)
+- [ ] Baseline threshold established
+- [ ] DSR > baseline verified
+- [ ] No data gaps detected
+- [ ] Results documented
+
+### OOS (Out-of-Sample) Performance
+- [ ] Bull market phase: DSR = ?
+- [ ] Bear market phase: DSR = ?
+- [ ] Sideways market phase: DSR = ?
+- [ ] Results within acceptable range
+- [ ] No systematic failure detected
+
+---
+
+## 📝 **Findings**
+
+### PBO Analysis
+```
+[To be completed during Phase 2]
+
+Observation:
+Conclusion:
+Impact: 
+```
+
+### DSR Analysis
+```
+[To be completed during Phase 2]
+
+Observation:
+Conclusion:
+Impact:
+```
+
+### OOS Phase Analysis
+```
+[To be completed during Phase 2]
+
+Bull Market DSR: TBD
+Bear Market DSR: TBD
+Sideways Market DSR: TBD
+
+Overall: TBD
+```
+
+---
+
+## ✅ **Gate 5 Phase 2 Completion**
+
+- [ ] All metrics collected
+- [ ] Validation complete
+- [ ] Evidence archived
+- [ ] Report approved
+- **Status:** ✅ **PASS** or ❌ **FAIL** (TBD)
+
+---
+
+**Next:** Phase 3 (Crash Recovery Rehearsal)