Add react-router-dom with two routes: "/" → MyScenariosPage (scenario grid with
search, create, open, delete against the scenarios API) and "/editor" → AppShell.
"Sair do cenário" returns to the list. New: use-scenarios hook, ScenarioCard,
MyScenariosPage (+ tests, 235 web tests green).
API: backfill legacy initialConditions rows missing instanceId so GET /scenarios
serializes under the updated schema.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
