Three root causes of blank page:
1. Modern.js layouts use <Outlet /> not {children} for nested routes
2. process.env not available in browser — guard with typeof checks
3. getEnv() schema required all fields — add defaults for browser context
Also: add source.entriesDir, runtime.router to modern.config.ts,
disable SSR temporarily until the SSR server build alias issue is
resolved (framework-level @_modern_js_src resolution).
Phase 4A: Define IFlightRoute, IMapMarker, IMapPolyline types; implement
searchDestinations and getFlightsMapCalendar API functions with 11 tests;
add useFlightsMapSearch, useFlightsMapCalendar hooks; add FEATURE_FLIGHTS_MAP
env var for feature flag gating.
gnezim