feat(nws, normalizers): add NWS hourly forecast normalization and enforce canonical float rounding

- Implement full NWS hourly forecast normalizer (raw.nws.hourly.forecast.v1 → weather.forecast.v1)
- Add GeoJSON forecast types and helpers for NWS gridpoint hourly payloads
- Normalize temperatures, winds, humidity, PoP, and infer WMO condition codes from forecast text/icons
- Treat forecast IssuedAt as EffectiveAt for stable, dedupe-friendly event IDs

- Introduce project-wide float rounding at normalization finalization
  - Round all float values in canonical payloads to 2 decimal places
  - Apply consistently across pointers, slices, maps, and nested structs
  - Preserve opaque structs (e.g., time.Time) unchanged

- Add SchemaRawNWSHourlyForecastV1 and align schema matching/comments
- Clean up NWS helper organization and comments
- Update documentation to reflect numeric wire-format and normalization policies

This establishes a complete, deterministic hourly forecast pipeline for NWS
and improves JSON output stability across all canonical weather schemas.

internal/standards/schema.go

@@ -15,6 +15,11 @@ const (
 	SchemaRawOpenMeteoCurrentV1   = "raw.openmeteo.current.v1"
 	SchemaRawOpenWeatherCurrentV1 = "raw.openweather.current.v1"
 
+	SchemaRawNWSHourlyForecastV1         = "raw.nws.hourly.forecast.v1"
+	SchemaRawOpenMeteoHourlyForecastV1   = "raw.openmeteo.hourly.forecast.v1"
+	SchemaRawOpenWeatherHourlyForecastV1 = "raw.openweather.hourly.forecast.v1"
+
 	// Canonical domain schemas (emitted after normalization).
 	SchemaWeatherObservationV1 = "weather.observation.v1"
+	SchemaWeatherForecastV1    = "weather.forecast.v1"
 )