IKEA Idasen Desk Plugin - use cm rather than percentage for more granular control

[Participant]

@Patschi I posted a more generalized version of your FR to apply to any entity exposed via a percentage slider:

Entities presenting a percentage-based control should allow for translation into absolute range and range limits

Covers, standing desks, and other devices offer control as a percentage.In some cases, either the user or the integration may know the absolute range of an entity. It’d be great if it were possible for percentage entities to offer a (user configurable) absolute range, and the ability to have that presented in the UI, history, etc instead of the percentage. Additionally, it’d be nice if the entity could have configurable min/max limiter, so we can ensure that HA never tries to move a device out …