feat: agent variants — migration, API, service integration, frontend, tests
- Migration 027: agent_variants table with single-active enforcement,
variant_id column on agent_performance_log
- API: full CRUD, clone from agent/variant, activate/deactivate,
per-variant performance metrics and history endpoints
- Services: extractor, event classifier, thesis rewriter all wired
to AgentConfigResolver with variant override support
- Frontend: variant list, comparison view, create/edit/clone forms,
activate/delete actions on Agents page
- Tests: API tests + 5 property-based tests (single-active invariant,
clone preservation, config resolution, slug determinism, update idempotence)
- Spec files for agent-variants feature
Celes Renata
7c23c044d7