Add support for equipment interlocks

Currently, if there is an interlock in place, home assistant will still allow toggling the entity on, but the next time the integration polls it will go back to off.

An example of this is a relay for a water feature that is interlocked with a pool cover sensor/switch so that the water feature cannot be turned on while the cover is closed.

We should detect this scenario in the configuration so that we can surface a message to the user if they attempt to toggle a device while it is interlocked.

Start by locating the integration's configuration handling and the code that processes entity toggles and polling updates. Trace how interlocked devices are represented, then define completion as detecting the configured interlock and surfacing a user-facing message instead of silently reverting the device to off.

Written by the indexing model from the issue text.