fix(binary_sensor): restore push updates from coordinator

Binary sensor _handle_coordinator_update() was empty, blocking all push updates
from coordinator. This prevented binary sensors from reflecting state changes
immediately after API fetch or error conditions.

Changes:
- Implement _handle_coordinator_update() to call async_write_ha_state()
- All binary sensors now receive push updates when coordinator has new data

Binary sensors affected:
- tomorrow_data_available: Now reflects data availability immediately after API fetch
- connection: Now shows disconnected state immediately on auth/API errors
- chart_data_export: Now updates chart data when price data changes
- peak_price_period, best_price_period: Get push updates when periods change
- data_lifecycle_status: Gets push updates on status changes

Impact: Binary sensors update in real-time instead of waiting for next timer
cycle or user interaction. Fixes stale state issue where tomorrow_data_available
remained off despite data being available, and connection sensor not reflecting
authentication failures immediately.

custom_components/tibber_prices/binary_sensor/core.py

@@ -217,11 +217,13 @@ class TibberPricesBinarySensor(TibberPricesEntity, BinarySensorEntity):
     @callback
     def _handle_coordinator_update(self) -> None:
         """Handle updated data from the coordinator."""
-        # Chart data export: No automatic refresh needed.
-        # Data only refreshes on:
-        # 1. Initial sensor activation (async_added_to_hass)
-        # 2. Config changes via Options Flow (triggers re-add)
-        # Hourly coordinator updates don't change the chart data content.
+        # All binary sensors get push updates when coordinator has new data:
+        # - tomorrow_data_available: Reflects new data availability immediately after API fetch
+        # - connection: Reflects connection state changes immediately
+        # - chart_data_export: Updates chart data when price data changes
+        # - peak_price_period, best_price_period: Update when periods change (also get Timer #2 updates)
+        # - data_lifecycle_status: Gets both push and Timer #2 updates
+        self.async_write_ha_state()
 
     @property
     def is_on(self) -> bool | None: