feat: add HDPS audio volume controls

[jkdevito]

Summary

• Add registered volume controls for HD-PS HDMI/DM Lite output mixers and analog auxiliary mixers.
• Expose controls through IBasicVolumeWithFeedback for Mobile Control discovery.
• Use stable output-specific device keys and include processor VTable compatibility fixes.

Testing

• dotnet clean && dotnet build

Reviewer Notes

• Controls are registered with DeviceManager during HDPS controller construction.

[Copilot]

Pull request overview

This PR adds per-output audio volume control devices for HD-PS chassis outputs (HDMI/DM Lite output mixers) and analog auxiliary mixers, exposing them via IBasicVolumeWithFeedback and registering them with DeviceManager for downstream discovery (e.g., Mobile Control).

Changes:

• Added HdPsAudioOutputController devices for outputs with an available output.Mixer, keyed per-output and registered in DeviceManager.
• Added HdPsAnalogAuxOutputController devices for each _chassis.AnalogAuxiliaryMixer, keyed per-mixer and registered in DeviceManager.
• Updated _chassis_OutputChange to fire volume/mute feedback updates for registered output volume controllers.

Suppressed comments (1)

src/Chassis/HdPsXxxController.cs:655

• VolumeDown uses integer division when scaling ramp time (... / 65535), which results in 0 for almost all current volume levels and makes CreateRamp effectively instantaneous. Use floating-point division (and the feedback value) so the ramp time scales correctly.

		public void VolumeDown(bool pressRelease)
		{
			if (pressRelease)
				_mixer.Volume.CreateRamp(0, (uint)(400 * (_mixer.Volume.UShortValue / 65535)));
			else
				_mixer.Volume.StopRamp();

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