I want to make my app available for use with automation in "Shortcuts". More specifically, I would like to make available an action that receives files as input in the Shortcuts app. I know that Adobe are offering such an action with lightroom ("import to lightroom") so I guess this is available to third party developers but I'm unable to figure out how to make my application's action available there too.
I've looked into Siri Kit and and Siri Shortcuts but the discussion there is concentrated around using Siri to invoke shortcuts, getting recommended etc. which is not relevant (I think) to what I'm trying to do. I don't understand how the Shortcuts app fits into that and I feel as there are two rather unrelated parts to this technology apple is marketing under "Siri Shortcuts" (invoking stuff via siri and automation) but I can only find documentation relevant to the voice stuff.
To sum up, I would appreciate any input regarding the following three questions
1. Where can I learn more about the shortcuts app, how to integrate with it and so on
2. How do I make my action available in the shortcuts app (I'm not sure that the term, for the entities in the shortcuts app)
3. How do I receive file input in that context