Removes the standalone resos_api_key from the forecasting app's own
system_config table. All credential fetches now go through
central_settings.get_resos_credentials() / get_resos_credentials_sync()
which pull from the Settings app (LXC 116) via the internal integration
endpoint — the same pattern already used for NewBook. The Resos API
Config section is removed from the forecasting Settings page; users
manage the key in the central Settings app instead.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Python FastAPI ML backend kept intact; auth replaced with central hnf_session cookie verification. Frontend rebuilt on React 18 + TS + Vite with stack design system, Plotly charts retained. Shared Postgres via DATABASE_URL; schema applied on startup.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
