Translate inverter and battery status states

[it-rec]

Proposed change

Both status sensors are already SensorDeviceClass.ENUM with options, and the integration ships translations for the config flow, options and repair issues. The entity states however are not translated, so the UI shows the raw option, for example B_STATUS_PRESERVE_CHARGE or I_STATUS_MPPT.

The readable text already exists in the integration - DEVICE_STATUS_TEXT and BATTERY_STATUS_TEXT are exposed as a status_text attribute - but attributes are not shown on the device page, so what a user actually reads is the raw constant.

This adds a translation_key to both status sensors and the corresponding entity.sensor.*.state sections, covering all 8 inverter and all 9 battery states.

Updated for review: all seven shipped languages are now filled in together - en, de, fr, it, nb, nl, pl. The first version only had en and de; that was wrong for this project and is fixed.

English reuses the existing wording from the two *_TEXT tables so there is only one set of terms in the project. I can verify en, de and fr myself; it, nb, nl and pl are my best effort from the English terms, so corrections from native speakers are welcome for those four.

This is not a breaking change. The state value is untouched, only the displayed text changes, so automations and templates comparing against B_STATUS_* or I_STATUS_* keep working.

Testing

Tested on a running Home Assistant instance with an inverter and a battery.

Registry after the change:

sensor.<inverter>_status      translation_key=inverter_status
sensor.<inverter>_b1_status   translation_key=battery_status

Translations served by the frontend API:

[de] B_STATUS_PRESERVE_CHARGE -> Ladung halten     [en] -> Preserve Charge
[de] I_STATUS_MPPT            -> Erzeugung         [en] -> Production

Two things I checked explicitly because they were the risk:

• State values unchanged. The sensors still report B_STATUS_DISCHARGE and I_STATUS_MPPT through the API after the change.
• Entity names unchanged. Setting a translation key can take over the entity name; it does not here, because both classes define name as a property.

Rebased on the current main.

Checklist

• Based on the latest upstream main.
• One subject only.
• Tested on a running instance.

[WillCodeForCats]

All translations must be updated together.

[it-rec]

All translations must be updated together.

Done