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/bluetooth_handler.py

@@ -47,7 +47,7 @@ class BmsBluetoothHandler:
         self,
         ble_device: BLEDevice,
         commands: list[bytes],
-        timeout: float = 5.0,
+        timeout: float = 3.0,
         retries: int = 3,
     ) -> list[bytes | None]:
         """Connect, send each command in sequence, disconnect.
@@ -63,7 +63,7 @@ class BmsBluetoothHandler:
             await client.start_notify(RX_CHAR_UUID, self._on_notify)
             # Give the BMS a moment to register the subscription before
             # we start sending commands
-            await asyncio.sleep(0.5)
+            await asyncio.sleep(0.3)
             return [
                 await self._request(client, cmd, timeout, retries)
                 for cmd in commands
@@ -147,7 +147,7 @@ class BmsBluetoothHandler:
                         _LOGGER.error("BLE write failed (attempt %d/%d): %s",
                                       attempt, retries, exc)
                         if attempt < retries:
-                            await asyncio.sleep(0.5)
+                            await asyncio.sleep(0.3)
                         continue
 
                 try:
@@ -157,7 +157,7 @@ class BmsBluetoothHandler:
                     _LOGGER.warning("BMS timeout (cmd=0x%s, attempt %d/%d)",
                                     command.hex(), attempt, retries)
                     if attempt < retries:
-                        await asyncio.sleep(0.5)
+                        await asyncio.sleep(0.3)
 
         return None