Add significant_weather_code attribute to Met Office Weather and Sensor entities

[tda2806]

Integration name

Met Office

Link to integration documentation on our website

homeassistant/components/metoffice

Describe the enhancement

Problem: The current Met Office integration maps the 31 unique "Significant Weather" codes from the DataHub API into a smaller subset of Home Assistant weather states (e.g., partlycloudy). This causes a loss of granularity for users who wish to use the official Met Office symbol set or display high-detail weather icons on external hardware (like E-Ink displays).

Proposal: Expose the raw numerical significantWeatherCode (0–30) as an additional attribute of the weather entity or as a separate sensor. This field is already present in the API response from the datapoint / DataHub library used by the integration.

Use cases

This allows for a 1:1 match with the symbols used on the official Met Office website and provides better alignment for UK-specific conditions like "Mist" (5) vs "Fog" (6), which are currently grouped together.

Anything else?

No response

[github-actions[bot]]

🏷️ I've automatically added the integration: metoffice label to help categorize this feature request.