Use metric.display_id for the default entity_id (de-duplicated prefix)

The entity_id suggestion now comes from metric.display_id (added in the
library), which strips the duplicated device-type prefix, e.g.
solarcharger_3_solarcharger_total_pv_yield -> solarcharger_3_total_pv_yield.

unique_id is intentionally left derived from metric.unique_id, so entity
identity is unchanged; Home Assistant applies a suggested entity_id only on
first creation, so existing entities keep their entity_id and only newly
created entities get the cleaner id. getattr fallback stays safe for bundled
libraries predating display_id.

Author: pos-ei-don

custom_components/victron_mqtt/entity.py

@@ -66,11 +66,20 @@ def __init__(
         self._attr_device_info = device_info
         if simple_naming:
             entity_id = f"{entity_platform}.{ENTITY_PREFIX}_{metric.unique_id}"
+            self._attr_unique_id = entity_id
         else:
-            entity_id = f"{entity_platform}.{ENTITY_PREFIX}_{installation_id}_{metric.unique_id}"
-            # you have to set the entity_id if we want to make the unique_id different from the default entity_id generation (which is based on the entity name)
-            self.entity_id = entity_id
-        self._attr_unique_id = entity_id
+            # unique_id stays derived from metric.unique_id, so an entity's
+            # identity never changes and existing entities keep their already
+            # registered entity_id untouched. The *suggested* entity_id uses
+            # metric.display_id, which de-duplicates the device-type prefix
+            # (e.g. solarcharger_3_solarcharger_total_pv_yield ->
+            # solarcharger_3_total_pv_yield). Home Assistant applies a suggested
+            # entity_id only when first creating an entity, so this affects NEW
+            # entities only; existing installs are unchanged. getattr keeps it
+            # safe if the bundled library predates display_id.
+            display_id = getattr(metric, "display_id", metric.unique_id)
+            self._attr_unique_id = f"{entity_platform}.{ENTITY_PREFIX}_{installation_id}_{metric.unique_id}"
+            self.entity_id = f"{entity_platform}.{ENTITY_PREFIX}_{installation_id}_{display_id}"
         self._attr_suggested_display_precision = metric.precision
         # Always set translation_key so HA can resolve state/option translations (e.g. select options).
         self._attr_translation_key = metric.generic_short_id.replace(