Fix connectToPreferredDevice parameter type to resolve compilation error

[Copilot]

What changed?

Changed connectToPreferredDevice function signature from device: Device to device: Device? = nil in AccessoryManager.swift.

Why did it change?

The function used nil-coalescing operator (device ?? fallback) on a non-optional parameter, which fails to compile. Making the parameter optional with a default value:

• Enables the nil-coalescing logic to work correctly
• Allows calling without arguments to auto-connect to preferred device
• Maintains backward compatibility with existing call sites

// Before (compilation error)
func connectToPreferredDevice(device: Device) {
    let preferredDevice = device ?? self.devices.first(...) // ❌ Won't compile
}

// After (compiles correctly)
func connectToPreferredDevice(device: Device? = nil) {
    let preferredDevice = device ?? self.devices.first(...) // ✅ Works
}

How is this tested?

Existing call sites in AccessoryManager+Discovery.swift continue to work unchanged. Function can now also be called with no arguments.

Screenshots/Videos (when applicable)

N/A - Internal API change with no UI impact.

Checklist

• My code adheres to the project's coding and style guidelines.
• I have conducted a self-review of my code.
• I have commented my code, particularly in complex areas.
• I have verified whether these changes require an update to existing documentation or if new documentation is needed, and created an issue in the docs repo if applicable.
• I have tested the change to ensure that it works as intended.

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