refactor(config): drop the androidtv media_player entity path end-to-end (t41)

The user ruling: this integration REPLACES both old integrations, so nothing may
depend on an androidtv/androidtv_remote entity anymore.

Removed:
* the setup-form field + its entity selector (CONF_ANDROIDTV_ENTITY is no longer
  offered, only read by the migration that drops it);
* the entity-derived unique_id derivation (_unique_id_from_atv_device, t29 G2)
  and, with it, every registry lookup for another integration's devices — the
  user step now sets NO unique_id at all; the protocol MAC learned during
  pairing is the identity;
* the Jellyfin auto-detect's second tier (the atv entity's friendly_name) — it
  now uses the entry name the user typed or the device name from discovery;
* the app-name and app-id tiers (media_player.app_name/app_id + the shared
  resolve_app_name chain, the Current App sensor, the sensor's state-change
  listener and its `_androidtv_state` helper) — the manager's store is the only
  source;
* the "transitional external entity" command tier in every path: `_cmd` and the
  pan-media_player service call are gone, and so is the fallback in _media_cmd,
  _remote_key_cmd, the §7 channel-digit sequence and the intent self-heal retry
  (an intent no transport served now surrenders to the truth instead of
  delegating);
* the entity-derived power signal (`_on_source_change`'s "device off clears the
  intent" check no longer watches another integration's entity; the power
  LADDER — protocol is_on → ADB wake → power switch — is unchanged).

turn_on/turn_off are native now: they send the protocol POWER key and, like the
remote entity, send nothing when the known state already matches (no superfluous
toggle). An ADB-only entry (protocol skipped) has no power write path — the
manager owns the socket and exposes no device-keyevent, which is what the old
delegation used to cover.

helpers.discover_adb_host — the one helper that derived a host from another
integration's config entry — is deleted; button.py (granted to this task) reads
the entry's own address fields instead of the entity, so the Pair ADB button
keeps working.

Present-day entries that still carry the key are unaffected (nothing reads it);
the v3 migration that drops it lands with the host unification.

Verified: 309 passed / 2 skipped, 310 / 1 with androidtvremote2, ruff clean,
drift engine exit 0 on HEAD (13 modules, 58 imports, 35 call arguments, 6
awaited HA calls) and 16 passed in the real-HA drift suite. The stub harness's
legacy service recorder became a watchdog: any HA service call from the media
player now fails the routing tests instead of being the expected outcome.

custom_components/nvidia_shield/sensor.py

@@ -12,7 +12,6 @@ from homeassistant.helpers.event import async_track_state_change_event
 
 from .connection import ShieldConnectionManager
 from .const import (
-    CONF_ANDROIDTV_ENTITY,
     CONF_APP_NAME_MAP,
     CONF_JELLYFIN_ENTITY,
     DOMAIN,
@@ -67,9 +66,9 @@ class NvidiaShieldSensorBase(SensorEntity):
 class NvidiaShieldCurrentAppSensor(NvidiaShieldSensorBase):
     """Current running app on the Shield.
 
-    Primary source: the androidtv entity's own state. When that entity is
-    unavailable, falls back to the ShieldConnectionManager's StateStore
-    (most recent visible ADB recent-task app).
+    Source: the ShieldConnectionManager's StateStore — the protocol current-app
+    push, or the most recent visible ADB recent-task app when that has not
+    reported (t41: our own transports only).
     """
 
     _attr_translation_key = "current_app"
@@ -77,7 +76,6 @@ class NvidiaShieldCurrentAppSensor(NvidiaShieldSensorBase):
 
     def __init__(self, hass: HomeAssistant, entry: ConfigEntry) -> None:
         super().__init__(hass, entry)
-        self._androidtv_entity = entry.data.get(CONF_ANDROIDTV_ENTITY, "")
         self._attr_unique_id = f"{DOMAIN}_{entry.entry_id}_current_app"
 
     def _manager(self) -> ShieldConnectionManager | None:
@@ -85,49 +83,30 @@ class NvidiaShieldCurrentAppSensor(NvidiaShieldSensorBase):
         return manager if isinstance(manager, ShieldConnectionManager) else None
 
     async def async_added_to_hass(self) -> None:
-        self._unsub_listeners.append(
-            async_track_state_change_event(
-                self.hass, [self._androidtv_entity], self._handle_state_change
-            )
-        )
         manager = self._manager()
         if manager is not None:
             # Refresh when the connection manager updates its store.
             self._unsub_listeners.append(manager.register_listener(self._handle_store_update))
 
-    @callback
-    def _handle_state_change(self, event: Event) -> None:
-        self.async_write_ha_state()
-
     @callback
     def _handle_store_update(self) -> None:
         self.async_write_ha_state()
 
-    def _androidtv_state(self):
-        """The configured androidtv entity's state object, or None."""
-        if not self._androidtv_entity:
-            return None
-        return self.hass.states.get(self._androidtv_entity)
-
     def _package(self) -> str | None:
-        """The raw foreground package (t40): entity tier, then the store.
+        """The raw foreground package from the manager's store (t41).
 
-        androidtv entity unavailable — StateStore priority chain (P3-3c):
-        protocol current_app push → ADB mResumedActivity → ADB recents.
+        StateStore priority chain (P3-3c): protocol current_app push → ADB
+        mResumedActivity → ADB recents.
         """
-        state = self._androidtv_state()
-        if state is not None:
-            package = state.attributes.get("app_id")
-            if package:
-                return package
         manager = self._manager()
-        if manager is not None:
-            foreground = manager.foreground_app
-            if foreground:
-                return foreground
-            running = manager.running_apps
-            if running:
-                return running[0].get("package")
+        if manager is None:
+            return None
+        foreground = manager.foreground_app
+        if foreground:
+            return foreground
+        running = manager.running_apps
+        if running:
+            return running[0].get("package")
         return None
 
     @property
@@ -135,17 +114,15 @@ class NvidiaShieldCurrentAppSensor(NvidiaShieldSensorBase):
         """The resolved friendly name (t40), not the raw package id.
 
         Exactly the ``media_player.app_name`` chain via the shared
-        ``resolve_app_name``: apps map → cached manifest label → androidtv
-        entity tier → the package text itself. A bare or unknown package shows
-        its package text rather than None, like the media player's app_name.
+        ``resolve_app_name``: apps map → cached manifest label → the package
+        text itself. A bare or unknown package shows its package text rather
+        than None, like the media player's app_name.
         """
         manager = self._manager()
-        state = self._androidtv_state()
         return resolve_app_name(
             self._package(),
             dict(self._entry.options.get(CONF_APP_NAME_MAP) or {}),
             manager.app_label if manager is not None else None,
-            state.attributes.get("app_name") if state is not None else None,
         )
 
     @property