- signals.sx: add def-store/use-store/clear-stores (L3 named stores) and emit-event/on-event/bridge-event (lake→island DOM events) - reactive-islands.sx: add event bridge, named stores, and plan pages - Remove ~plan-reactive-islands-content from plans.sx - Update nav-data.sx and docs.sx routing accordingly Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>