Verifies that all public API modules have documentation and a stability-tier declaration, and generates a manifest.
Each public Parapet module must include an ExDoc admonition callout in its
@moduledoc to declare its stability tier:
- Stable:
> #### Stable {: .info} - Experimental:
> #### Experimental {: .warning}
Modules in the Parapet.Internal.* or Parapet.TestSupport.* namespaces and
modules containing .Resolvable in their name are excluded from this check.
(This also catches the terminal protocol module Parapet.SLO.Resolvable and
its auto-generated defimpl dispatch modules.)