Bounded visual automation builder

SHIPPED 2026-06-30 (launch-scope #15 build-or-descope decision: built): staff author automations on a bounded React Flow canvas — trigger/action catalog, validation, draft/publish/disable — backed by the native outbox interpreter (ADR 0030; no out-of-process engine). E2E + module integration tests in CI. Remaining hardening lives under launch hardening: compile-to-engine, real-driver proof, automation:author authz wiring.