feat: shared DisplayCoordinator + optional API token

- Introduce DisplayCoordinator polling /api/display/monitors once per
  cycle and fan out to all per-display entities via CoordinatorEntity.
  Removes ~9x redundant requests per polling cycle that came from each
  binary_sensor/number/select/sensor/switch entity calling
  get_display_monitors() in its own async_update.
- Optimistic write-through via coordinator.apply_optimistic(...) keeps
  sibling entities in sync after slider/select writes without an extra
  network round-trip.
- Make CONF_TOKEN optional. The media server already supports running
  without auth (auth_enabled() returns False when api_tokens is empty),
  so the integration omits the Authorization header and ?token= query
  from REST/WS/album-art URLs when no token is configured. Server-side
  auth-enabled rejections still surface as invalid_auth in the UI.
- Bump manifest version to 0.3.2.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

custom_components/remote_media_player/sensor.py

@@ -10,9 +10,10 @@ from homeassistant.config_entries import ConfigEntry
 from homeassistant.core import HomeAssistant
 from homeassistant.helpers.entity import EntityCategory
 from homeassistant.helpers.entity_platform import AddEntitiesCallback
+from homeassistant.helpers.update_coordinator import CoordinatorEntity
 
-from .api_client import MediaServerClient, MediaServerError
 from .const import DOMAIN
+from .display_coordinator import DisplayCoordinator
 from .display_device import display_device_info
 
 _LOGGER = logging.getLogger(__name__)
@@ -24,17 +25,16 @@ async def async_setup_entry(
     async_add_entities: AddEntitiesCallback,
 ) -> None:
     """Set up per-display sensor entities."""
-    client: MediaServerClient = hass.data[DOMAIN][entry.entry_id]["client"]
+    coordinator: DisplayCoordinator = hass.data[DOMAIN][entry.entry_id][
+        "display_coordinator"
+    ]
 
-    try:
-        monitors = await client.get_display_monitors()
-    except MediaServerError as err:
-        _LOGGER.error("Failed to fetch display monitors: %s", err)
+    if not coordinator.data:
         return
 
     entities = [
-        DisplayResolutionSensor(client, entry, monitor)
-        for monitor in monitors
+        DisplayResolutionSensor(coordinator, entry, monitor)
+        for monitor in coordinator.data.values()
         if monitor.get("resolution")
     ]
 
@@ -43,7 +43,7 @@ async def async_setup_entry(
         _LOGGER.info("Added %d display sensor entities", len(entities))
 
 
-class DisplayResolutionSensor(SensorEntity):
+class DisplayResolutionSensor(CoordinatorEntity[DisplayCoordinator], SensorEntity):
     """Diagnostic sensor reporting the EDID-derived display resolution."""
 
     _attr_has_entity_name = True
@@ -53,24 +53,17 @@ class DisplayResolutionSensor(SensorEntity):
 
     def __init__(
         self,
-        client: MediaServerClient,
+        coordinator: DisplayCoordinator,
         entry: ConfigEntry,
         monitor: dict[str, Any],
     ) -> None:
-        """Initialize the display resolution sensor."""
-        self._client = client
+        super().__init__(coordinator)
         self._monitor_id: int = monitor["id"]
-        self._attr_native_value = monitor.get("resolution")
         self._attr_unique_id = f"{entry.entry_id}_display_resolution_{self._monitor_id}"
         self._attr_device_info = display_device_info(entry, monitor)
 
-    async def async_update(self) -> None:
-        """Refresh resolution from the server (rarely changes)."""
-        try:
-            monitors = await self._client.get_display_monitors()
-            for monitor in monitors:
-                if monitor["id"] == self._monitor_id:
-                    self._attr_native_value = monitor.get("resolution")
-                    break
-        except MediaServerError as err:
-            _LOGGER.error("Failed to refresh resolution for monitor %d: %s", self._monitor_id, err)
+    @property
+    def native_value(self) -> str | None:
+        if self.coordinator.data is None:
+            return None
+        return self.coordinator.data.get(self._monitor_id, {}).get("resolution")