1. Yes, it's the one in the app/ folder.

2. Features can not depend on other features, otherwise you'll find yourself dealing with circular dependencies very soon. Things like authentication or database should be treated as utilities. You may want to create an additional layer of abstraction (we call it "core" at Tide) to separate utilities of different levels of abstraction, i.e. analyzer config and flow builder from authentication mechanism and database.

3. Utilities can not depend on features, hence the navigation package can not be one. I'd recommend putting it under the app folder, so that the dependency direction will always be: app -> feature -> utility.