Manage per-user WeatherSource instances via FeedSourceProvider,
following the same pattern as LocationService. Wire into
FeedEngineService so weather data is included in the feed.
Co-authored-by: Ona <no-reply@ona.com>
- Add apps/aris-backend package with Hono server
- Add /health endpoint
- Add backend-spec.md with design decisions
Co-authored-by: Ona <no-reply@ona.com>