Expand description
Phase 3a — db_agents dual-write helpers.
Every mutation on db_agent_definitions / db_agent_instances
mirrors into db_agents so a later read-migration PR (Phase 3b)
can flip readers over with confidence. Dual-write failures LOG +
CONTINUE — the old tables remain authoritative until Phase 3b.
See docs/specs/SPEC_AGENT_CONCEPT_CONSOLIDATION_2026_05_24.md.
Extracted from store.rs in Phase R.5 of the storage
modularization plan
(docs/specs/SPEC_STORE_MODULARIZATION_2026_05_27.md). This
whole file goes away in Phase 3c when the legacy tables are
dropped — keeping it isolated makes that future deletion clean.