Add NOAA NWS weather fallback

Data/Weather/noaa_nws_us_fallback.json

@@ -0,0 +1,20 @@
+{
+  "schema_version": 1,
+  "provider_id": "noaa-nws",
+  "provider_name": "NOAA National Weather Service API",
+  "provider_docs_url": "https://www.weather.gov/documentation/services-web-api",
+  "points_endpoint": "https://api.weather.gov/points",
+  "api_key_required": false,
+  "scope": "United States and NWS-covered territories only",
+  "eligibility_rule": "Use as fallback or enrichment only when tile center coordinates are inside the approximate NWS latitude/longitude coverage window.",
+  "request_flow": [
+    "GET /points/{latitude},{longitude}",
+    "Read properties.forecastGridData",
+    "GET forecastGridData for gridded temperature, precipitation probability, and wind speed"
+  ],
+  "agrarian_mapping": {
+    "temperature": "NWS grid temperature can feed RegionalObservedTemperatureC when Open-Meteo is unavailable for a US tile.",
+    "precipitation": "probabilityOfPrecipitation enriches rain/fallback mapping until precipitation amount mapping is implemented.",
+    "wind": "windSpeed enriches ColdWind and Storm fallback mapping."
+  }
+}