Handle signed-in users without organization access

[PabloDinella]

Summary

• Add a dedicated no-organization-access screen for signed-in users who are not connected to any CareTogether org/location
• Route post-login root traffic through a new RootRoute that redirects to a valid location or shows the no-access screen
• Guard scoped /org/:organizationId/:locationId routes so stale URLs from another account do not set invalid location context
• Extract access route helpers and screen components into src/caretogether-pwa/src/Access

Validation

• npm run type-check
• npx eslint src/AppRoutes.tsx src/Access/accessRouteHelpers.ts src/Access/NoOrganizationAccessScreen.tsx src/Access/RootRoute.tsx --ext ts,tsx --report-unused-disable-directives --max-warnings 0
• npm run build