Use compact primary-key tables for soft records and replay versions. Preserve provenance, tombstones, and cached dependencies through an atomic migration. Keep indexes and references instead of duplicate graph records, and convert SQL rows directly into the final edge buffer. Add reproducible scale benchmarks and migration coverage. The 100,000-edge fixture uses 23 percent fewer database pages and 27 percent fewer graph-load and selection allocations. Document migration space requirements and the remaining global-graph limit. Task: tsk-24