How can I tell the host, that a parameter created via AudioProcessorValueTreeState::createAndAddParameter() is not automatable ?
currently AudioProcessorValueTreeState::Parameter is not exposed and is does not override isAutomatable(). So I think a code-change is required: one way would be possible to expose the internal AudioProcessorValueTreeState::Parameter class and add setIsAutomatable() that simply set a bool return it via isAutomatable(). Another way would be to add those setters directly to the AudioProcessorParameter class.
It would also quite useful to completely hide a parameter from the host while still being able to use the AudioProcessorValueTreeState::Attachment awesomeness.