Dry to Setpoint Support

[KazWolfe]

Home Assistant's climate integration supports the ability to set a target humidity, allowing (de)humidifiers to run until a certain specific percentage has been reached.

While Mitsubishi devices do not support setting a humidity percentage (or, at least, I haven't found any reference to such), an ESP32 can do this by simply tracking humidity accordingly and turning off the unit once the target humidity has been reached.

Considerations

Since this is not a native feature, it will need to be managed completely in the ESPHome platform. As such:

• If DRY mode is set from the MHK unit (otherwise "unmanaged"), the humidity setpoint shall be set to 0% or equivalent.
• If using managed dry mode, the device should run in DRY mode until the target humidity has been reached, at which point it is transitioned to off. Any change from the MHK (including turning the unit on) will disable managed mode.
  • In managed mode, the MHK2 should ideally be told that the heat pump is still in DRY mode even when it's not running.

[Sammy1Am]

I can't remember for sure, but I think some Mitsubishi units have a setting (or maybe it's just in Kumo) where you can set a minimum temperature for DRY mode (I think that's the Supports dry temperature bit from Extended Connect Response). I'm guessing that in DRY mode on units that support this, we can just set the target temperature normally, but for units that don't support it we may want to emulate that to prevent things from getting too cold 🥶.

And then I guess if we're going to support systems that don't natively support at target DRY setpoint, we could actually just emulate a full-on DRY mode on the ESP by setting it to COOL and the lowest fan speed. It wouldn't necessarily be as effective as the true DRY mode, but if users were more concerned with humidity than temperature, someone might want it. (Probably stick to native DRY to start with)