Clarify MotorHat disposal/ownership semantics in README

[Copilot]

The MotorHat README showed a DCMotor being created but never disposed, leaving it unclear whether motors need separate disposal, whether dispose order matters, and whether disposing both the MotorHat and its motors causes conflicts.

Confirmed from the source that there is no conflict: MotorHat.Dispose() stops all channels it created and disposes the underlying PCA9685, while DCMotor3Pwm.Dispose() only stops its PWM pins (never disposes them). Disposal is therefore idempotent and order-independent.

Changes

• Added a "Resource management (disposing)" section to src/devices/MotorHat/README.md covering the ownership model:
  • Disposing the MotorHat alone releases every motor/servo/PWM channel it handed out.
  • Disposing motors as well is safe (stop-only); dispose order is irrelevant.
• Included a corrected PumpController-style example forwarding disposal to the MotorHat.

public void Dispose()
{
    // Disposing the MotorHat stops and releases every motor/channel it created.
    // Order is not important and disposing the motors as well would be safe.
    _motorHat.Dispose();
}

[Copilot]

Pull request overview

This PR updates the MotorHat device documentation to clarify resource ownership and disposal behavior when creating motors/servos/PWM channels from MotorHat, aiming to prevent confusion about whether returned objects must be disposed and in what order.

Changes:

• Adds a new “Resource management (disposing)” section describing MotorHat ownership and cleanup responsibilities.
• Provides updated usage guidance and a wrapper-class example that forwards disposal to MotorHat.

[krwq]

Suggested change

	{
	// Disposing the MotorHat stops and releases every motor/channel it created.
	// If you dispose motors explicitly, dispose them before disposing the MotorHat.
	}
	{
	// Dispose motors first (their Dispose stops the PWM channels),
	// then dispose the MotorHat which releases the underlying PCA9685 + I2C device.
	foreach (var motor in _motors)
	{
	motor.Dispose();
	}
	_motorHat.Dispose();
	}

[krwq]

@copilot fix it with correct indent

[Copilot]

Done — updated the Dispose example with the motors-first loop and correct indentation in dbdd54a.