Warm/hot/heatwave tiers (ascending peak_above_c thresholds) override the
global ac_occupied template when today's forecast peak clears one, picked
once at the occupied-state transition so a guest's later manual adjustment
is never stomped. New lib/weather.js fetches the peak via Met Office
DataHub (if configured in settings) or Open-Meteo (no key needed) as a
fallback, TTL-cached with a stale-fallback window on fetch failure.
Zone-level per-field overrides still apply on top of a picked tier.
Thresholds/templates live in hvac_defaults.ac_occupied_tiers (existing
JSONB config blob, no migration) and are editable on the Settings page's
new Weather Compensation table. Hotel lat/lon and the optional Met Office
API key live centrally in the settings app (hotel_location/met_office
integrations), not hvac-local, for reuse by other apps later.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>