Add temporal history competitor gap report

[yvette-carlisle]

Summary

• add a report-only temporal/history competitor gap report for ELF
• update the benchmark index with the new report
• record fresh evidence boundaries for ELF+mem0 lifecycle smoke, ELF/qmd memory evolution, Graphiti/Zep typed blocker, and Letta non-comparable state

Claim boundary

• does not implement ELF optimization
• does not claim the overall objective is complete
• does not claim ELF beats all tracked competitors
• separates fixture, baseline smoke, live real-world, research-gate, and blocked evidence classes

Validation

• jq empty docs/research/2026-06-11-temporal-history-competitor-gap-report.json
• git diff --cached --check
• playbook semantic_drift_audit.py
• jq artifact-to-report assertions for mem0 baseline, ELF/qmd memory_evolution, and Graphiti/Zep provider blocker