feat(displays): per-display devices + DDC/CI capability entities

Restructure how displays are exposed in Home Assistant:

Each physical monitor is now its own HA device linked to the media-server
hub via `via_device`. The hub keeps the media_player + script buttons; per-
display devices hold the power switch, brightness slider, and the new
capability entities. This lets users place displays in their own area/room
and keeps related entities grouped together in the UI.

New platforms:
- sensor: DisplayResolutionSensor (diagnostic, from EDID)
- binary_sensor: DisplayPrimaryBinarySensor + DisplayPowerControlBinarySensor
  (both diagnostic; help users see why a power switch is or isn't created)
- select: DisplayInputSourceSelect (HDMI1/DP1/...), DisplayColorPresetSelect
  (color temperature), DisplayPictureModeSelect (VCP 0xDC scene modes)
- number: added DisplayContrastNumber alongside brightness

Other changes:
- display_device helper centralises the per-display DeviceInfo; pulls real
  manufacturer/model from EDID; device name no longer prepends the hub
  title since via_device already shows the hierarchy.
- api_client gains set_display_{contrast,input_source,color_preset,picture_mode}
  and stops forcing `?refresh=true` on every poll so HA can ride the
  server's TTL cache instead of triggering full DDC/CI probes per entity.
- select / number entities now check the server's `success` flag and re-
  sync from the actual monitor state when a write was silently rejected
  (some monitors honor reads but ignore writes for certain DDC/CI codes).

Bumps manifest.json to 0.3.0 - the device topology change is user-visible
and existing brightness/power entities migrate to per-display devices on
first reload (unique_ids are preserved).

custom_components/remote_media_player/number.py

@@ -8,11 +8,11 @@ from typing import Any
 from homeassistant.components.number import NumberEntity, NumberMode
 from homeassistant.config_entries import ConfigEntry
 from homeassistant.core import HomeAssistant
-from homeassistant.helpers.entity import DeviceInfo
 from homeassistant.helpers.entity_platform import AddEntitiesCallback
 
 from .api_client import MediaServerClient, MediaServerError
 from .const import DOMAIN
+from .display_device import display_device_info
 
 _LOGGER = logging.getLogger(__name__)
 
@@ -22,7 +22,7 @@ async def async_setup_entry(
     entry: ConfigEntry,
     async_add_entities: AddEntitiesCallback,
 ) -> None:
-    """Set up display brightness number entities from a config entry."""
+    """Set up display brightness + contrast number entities from a config entry."""
     client: MediaServerClient = hass.data[DOMAIN][entry.entry_id]["client"]
 
     try:
@@ -31,25 +31,23 @@ async def async_setup_entry(
         _LOGGER.error("Failed to fetch display monitors: %s", err)
         return
 
-    entities = [
-        DisplayBrightnessNumber(
-            client=client,
-            entry=entry,
-            monitor=monitor,
-        )
-        for monitor in monitors
-        if monitor.get("brightness") is not None
-    ]
+    entities: list[Any] = []
+    for monitor in monitors:
+        if monitor.get("brightness") is not None:
+            entities.append(DisplayBrightnessNumber(client, entry, monitor))
+        if monitor.get("contrast_supported"):
+            entities.append(DisplayContrastNumber(client, entry, monitor))
 
     if entities:
         async_add_entities(entities)
-        _LOGGER.info("Added %d display brightness entities", len(entities))
+        _LOGGER.info("Added %d display number entities", len(entities))
 
 
 class DisplayBrightnessNumber(NumberEntity):
     """Number entity for controlling display brightness."""
 
     _attr_has_entity_name = True
+    _attr_name = "Brightness"
     _attr_native_min_value = 0
     _attr_native_max_value = 100
     _attr_native_step = 1
@@ -67,27 +65,9 @@ class DisplayBrightnessNumber(NumberEntity):
         self._client = client
         self._entry = entry
         self._monitor_id: int = monitor["id"]
-        self._monitor_name: str = monitor.get("name", f"Monitor {monitor['id']}")
-        self._resolution: str | None = monitor.get("resolution")
         self._attr_native_value = monitor.get("brightness")
-
-        # Use resolution in name to disambiguate same-name monitors
-        display_name = self._monitor_name
-        if self._resolution:
-            display_name = f"{self._monitor_name} ({self._resolution})"
-
         self._attr_unique_id = f"{entry.entry_id}_display_brightness_{self._monitor_id}"
-        self._attr_name = f"Display {display_name} Brightness"
-
-    @property
-    def device_info(self) -> DeviceInfo:
-        """Return device info."""
-        return DeviceInfo(
-            identifiers={(DOMAIN, self._entry.entry_id)},
-            name=self._entry.title,
-            manufacturer="Remote Media Player",
-            model="Media Server",
-        )
+        self._attr_device_info = display_device_info(entry, monitor)
 
     async def async_set_native_value(self, value: float) -> None:
         """Set the brightness value."""
@@ -108,3 +88,58 @@ class DisplayBrightnessNumber(NumberEntity):
                     break
         except MediaServerError as err:
             _LOGGER.error("Failed to update brightness for monitor %d: %s", self._monitor_id, err)
+
+
+class DisplayContrastNumber(NumberEntity):
+    """Number entity for controlling DDC/CI display contrast."""
+
+    _attr_has_entity_name = True
+    _attr_name = "Contrast"
+    _attr_native_min_value = 0
+    _attr_native_max_value = 100
+    _attr_native_step = 1
+    _attr_native_unit_of_measurement = "%"
+    _attr_mode = NumberMode.SLIDER
+    _attr_icon = "mdi:contrast-circle"
+
+    def __init__(
+        self,
+        client: MediaServerClient,
+        entry: ConfigEntry,
+        monitor: dict[str, Any],
+    ) -> None:
+        """Initialize the display contrast entity."""
+        self._client = client
+        self._monitor_id: int = monitor["id"]
+        self._attr_native_value = monitor.get("contrast")
+        self._attr_unique_id = f"{entry.entry_id}_display_contrast_{self._monitor_id}"
+        self._attr_device_info = display_device_info(entry, monitor)
+
+    async def async_set_native_value(self, value: float) -> None:
+        """Set the contrast value."""
+        try:
+            result = await self._client.set_display_contrast(self._monitor_id, int(value))
+        except MediaServerError as err:
+            _LOGGER.error("Failed to set contrast for monitor %d: %s", self._monitor_id, err)
+            return
+        if not result.get("success"):
+            _LOGGER.warning(
+                "Monitor %d rejected contrast %d (DDC/CI silently dropped)",
+                self._monitor_id, int(value),
+            )
+            await self.async_update()
+            self.async_write_ha_state()
+            return
+        self._attr_native_value = int(value)
+        self.async_write_ha_state()
+
+    async def async_update(self) -> None:
+        """Fetch updated contrast from the server."""
+        try:
+            monitors = await self._client.get_display_monitors()
+            for monitor in monitors:
+                if monitor["id"] == self._monitor_id:
+                    self._attr_native_value = monitor.get("contrast")
+                    break
+        except MediaServerError as err:
+            _LOGGER.error("Failed to update contrast for monitor %d: %s", self._monitor_id, err)