feat: Connect to devices asynchronously

[allenporter]

Update the device manager to not block on connecting to devices immediately, but instead connect to them asynchronously in the background. Once they connect, the devices will reconnect on their own (e.g. using the mqtt session or local channel behavior).

Add a test that exercises the behavior of an unsuccessful connect with retries in the background.

[Copilot]

Pull Request Overview

This PR updates the device manager to connect to devices asynchronously in the background instead of blocking on connection, allowing the application to continue operating while devices connect. Connection failures are automatically retried with exponential backoff.

• Changed device_manager.py to call start_connect() instead of await connect() when discovering devices
• Added start_connect() method with exponential backoff retry logic in device.py
• Added test coverage for connection failure and retry behavior

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 4 comments.

File	Description
roborock/devices/device_manager.py	Changed from blocking await connect() to non-blocking start_connect() call
roborock/devices/device.py	Added start_connect() method with retry loop, exponential backoff constants, and task cancellation in close()
tests/devices/test_device_manager.py	Added test fixtures and test case for connection failure scenarios with retry behavior

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[Lash-L]

Maybe I'm sleep deprived but can you double check this is the right functionality? Won't this reopen the connection on close()

[allenporter]

The self._connect_task is a task started in start_connect. That start event happens once there, and gets kicked off in the background. Then in close, we cancel the task. This line will wait for the task to complete -- either because it already completed or because its waiting for cancellation to finish.

This has an example https://docs.python.org/3/library/asyncio-task.html#asyncio.Task.cancel and what we're doing here is similar to how the main example looks.

[Lash-L]

Ah yes that makes sense. Looking at it again. Thank you for the explanation.