As an admin, I want to decide the level of privacy of my space when I create it, so that I can ensure the right people have access to the right content

Acceptance criteria

When creating a space, the admin must choose between Public or Private before proceeding.
Public space:
- Anyone can find and access the space with a link. All content is visible by default.
- Admins can mark specific folders or documents as private from contextual options (3 dots).
- Admins can set a document as private at the moment of creation (private document).
- Mental model: "My space is public, but I've chosen to lock these specific things."
Private space:
- Only invited members can see and access the space and its content
- Privacy allow granular control, from space to documents
- The privacy settings can be changed later from space settings.