Context
For the ACM Hypertext repository, many papers may not be Open Access, and Mark expects the repository should therefore not be indexed by Google.

We should support explicit search-engine indexing controls at the Space and potentially Document level. This also gives us a concrete example of how Seed supports digital-rights requirements.

Requirements

Add an indexing property to a Space, inherited by its documents by default.

Allow a document to override the Space setting if needed.

When disabled, render the appropriate robots directive, e.g. noindex.

Consider whether link crawling should be controlled separately with nofollow.

Make the setting visible/configurable in publishing or Space settings.

Use case
The ACM Hypertext repository can be publicly accessible through Seed while explicitly telling search engines not to index its papers.