feat(entity): expose integration version as sw_version in device info

Read the version field from manifest.json at import time via a new
INTEGRATION_VERSION constant in const.py. Pass it as sw_version to
DeviceInfo in TibberPricesEntity so the current integration version
is visible in the HA device registry.

Impact: Device page in HA now shows the installed integration version
under firmware/software version.

custom_components/tibber_prices/const.py

@@ -20,6 +20,9 @@ if TYPE_CHECKING:
 DOMAIN = "tibber_prices"
 LOGGER = logging.getLogger(__package__)
 
+# Integration version from manifest.json (used for DeviceInfo sw_version)
+INTEGRATION_VERSION: str = json.loads((Path(__file__).parent / "manifest.json").read_text(encoding="utf-8"))["version"]
+
 # Data storage keys
 DATA_CHART_CONFIG = "chart_config"  # Key for chart export config in hass.data
 DATA_CHART_METADATA_CONFIG = "chart_metadata_config"  # Key for chart metadata config in hass.data

custom_components/tibber_prices/entity.py

@@ -5,7 +5,7 @@ from __future__ import annotations
 from homeassistant.helpers.device_registry import DeviceEntryType, DeviceInfo
 from homeassistant.helpers.update_coordinator import CoordinatorEntity
 
-from .const import ATTRIBUTION, DOMAIN, get_home_type_translation, get_translation
+from .const import ATTRIBUTION, DOMAIN, INTEGRATION_VERSION, get_home_type_translation, get_translation
 from .coordinator import TibberPricesDataUpdateCoordinator
 
 
@@ -41,6 +41,7 @@ class TibberPricesEntity(CoordinatorEntity[TibberPricesDataUpdateCoordinator]):
             manufacturer="Tibber",
             model=translated_model,
             serial_number=home_id or None,
+            sw_version=INTEGRATION_VERSION,
             configuration_url="https://developer.tibber.com/explorer",
         )