feat: support the DYD-P40

[Dixiao-L]

What breaks today

A DYD-P40 (product id d71936c6951c11f0a8200242ac480009) reports WindSpeed = 5, which DeyeFanSpeed doesn't define, so every poll raises:

File ".../libdeye/device_state.py", line 92, in _parse_state_fog
    self.fan_speed = DeyeFanSpeed(state.get("WindSpeed", DeyeFanSpeed.STOPPED))
ValueError: 5 is not a valid DeyeFanSpeed

The enum member alone isn't enough. Consumers map state through ordered_list_item_to_percentage(feature_config["fan_speed"], …), which raises for a speed absent from the product's list — and this product has no PRODUCT_FEATURE_CONFIG entry, so it inherits the default listing speeds 1–4.

Everything here was measured, not guessed

The product catalogue carries no capability metadata (the P40 entry has only name/brand/picture/config_guide), so I set each property on the real appliance and read it back, capturing a baseline first and restoring it afterwards (zero drift):

Property	Accepted	Rejected
Mode	1, 2, 3, 4, 6	0 (MANUAL), 5
WindSpeed	1, 2, 3, 5	4 (FULL)
SetHumidity	40–70	20, 25, 30, 35, 75, 80, 85, 90
NegativeIon	1 → sticks	—
SwingingWind	1 → sticks	—
WaterPump	—	1 → reads back 0

Since 4 is rejected while 5 is accepted, 5 is not a step above FULL — most likely an auto/smart speed. I named it UNKNOWN_SPEED, following the existing convention for unidentified values (DeyeDeviceMode already carries UNKNOWN_MODE and UNKNOWN_MODE_2). Happy to rename if you know what it is.

Two further observations, not addressed here

Recording them since they affect how this model maps, but neither is expressible in a product config:

1. Fan is read-only on this model and stays 1 even with Power = 0 (CompressorStatus goes to 0 instead). _parse_state_fog maps it to fan_running, so that flag is effectively stuck true — which makes the derived "is it running" state wrong.
2. UV is settable on this unit but has no model here.

Separate PR against ha-deye-dehumidifier (#108) fixes an independent issue that had to be cleared before any of this was reachable: the Fog client isn't connected for devices whose platform isn't exactly Fog, and the P40 reports platform = 3.