Forward requested event type in Home Assistant event subscriptions

[Copilot]

SubscribeToHomeAssistantEventsAsync(eventType, ...) was constructing subscribe_events commands without event_type, causing every non-cached subscription to become an all-events subscription. For non-admin tokens this can fail as unauthorized; for admin tokens it silently over-subscribes.

• Behavior change

  • HomeAssistantConnection.SubscribeToHomeAssistantEventsInternalAsync now forwards the requested eventType onto SubscribeEventCommand.EventType.
  • This preserves the existing optimized cached path for null/empty event types and only changes the specific-event subscription path.

• Regression coverage

  • Added a focused HassClient unit test that verifies subscribing to "state_changed" sends a SubscribeEventCommand with EventType == "state_changed".

• Result

  • Specific event subscriptions now produce the expected websocket payload instead of omitting event_type.

await connection.SubscribeToHomeAssistantEventsAsync("state_changed", cancellationToken);

// now sends:
new SubscribeEventCommand
{
    EventType = "state_changed"
};

• Fixes SubscribeToHomeAssistantEventsAsync never sends the requested event_type #1443

[helto4real]

I think this look pretty good but will do a proper reivew when it is out of draft

[FrankBakkerNl]

Fix is solid. This was clearly forgotten as the argument is never used. Our own code never passes a value other than null here (except for some tests) so it would not break.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 83%. Comparing base (250a6f8) to head (5bade2b).

Additional details and impacted files

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##           main   #1471   +/-   ##
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  Coverage    83%     83%           
====================================
  Files       201     201           
  Lines      4173    4176    +3     
  Branches    477     477           
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+ Hits       3480    3483    +3     
  Misses      496     496           
  Partials    197     197           

Flag	Coverage Δ
unittests	83% <100%> (+<1%)	⬆️

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