Use BLE device name, add hard poll timeout, tighten request timing

- Device name: coordinator now takes name=entry.title so the HA device card
  shows the actual BLE advertised name instead of "Xiaoxiang Smart BMS"
- Hard poll timeout: each poll is capped at (poll_interval - 3)s via
  asyncio.wait_for so a stalled poll can't bleed into the next cycle
- Request timeout: 5s → 3s (BMS should reply in <1s under normal conditions)
- Retry delay: 0.5s → 0.3s between retries

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

custom_components/xiaoxiang_bms/coordinator.py

@@ -1,6 +1,7 @@
 """DataUpdateCoordinator for the Xiaoxiang Smart BMS."""
 from __future__ import annotations
 
+import asyncio
 import logging
 from datetime import timedelta
 
@@ -27,6 +28,7 @@ class BmsCoordinator(DataUpdateCoordinator[dict]):
         hass: HomeAssistant,
         address: str,
         poll_interval: int,
+        name: str = "Xiaoxiang Smart BMS",
     ) -> None:
         super().__init__(
             hass,
@@ -35,6 +37,8 @@ class BmsCoordinator(DataUpdateCoordinator[dict]):
             update_interval=timedelta(seconds=poll_interval),
         )
         self.address = address
+        self._device_name = name
+        self._poll_timeout = max(poll_interval - 3, 10)  # hard cap, leaves 3s slack
         self._handler = BmsBluetoothHandler(address)
         self.hw_version: str | None = None
 
@@ -46,7 +50,7 @@ class BmsCoordinator(DataUpdateCoordinator[dict]):
     def device_info(self) -> DeviceInfo:
         return DeviceInfo(
             identifiers={(DOMAIN, self.address)},
-            name="Xiaoxiang Smart BMS",
+            name=self._device_name,
             manufacturer="Xiaoxiang",
             model=self.hw_version or "Smart BMS",
         )
@@ -79,7 +83,14 @@ class BmsCoordinator(DataUpdateCoordinator[dict]):
             commands.append(CMD_VERSION)
 
         try:
-            responses = await self._handler.poll(device, commands)
+            responses = await asyncio.wait_for(
+                self._handler.poll(device, commands),
+                timeout=self._poll_timeout,
+            )
+        except asyncio.TimeoutError:
+            raise UpdateFailed(
+                f"BMS poll timed out after {self._poll_timeout}s"
+            )
         except Exception as exc:
             raise UpdateFailed(f"BMS poll failed: {exc}") from exc