Path inconsistency in listings

Example repo: http://github.com/cwickham/listings

cc @cscheid

Relative links for listing contents

I want to be able to have a listing on a post, that gives other “recent
posts”. E.g. on posts/post-with-code/index.qmd.

This doesn’t work:

posts/post-with-code/index.qmd

listing:
  contents: /posts

WARN: The listing in 'posts/post-with-code/index.qmd' using the following contents:
- /posts
doesn't match any files or folders.

Neither does this:

posts/post-with-code/index.qmd

listing:
  contents: ../

WARN: The listing in 'posts/post-with-code/index.qmd' using the following contents:
- ../
doesn't match any files or folders.

This works, but why?:

posts/post-with-code/index.qmd

listing:
  contents: ../*/index.qmd

Project relative links for listing template

It might be nice to specify a global listing template in
_metadata.yml, e.g.

_metadata.yml

listing:
  template: blog.ejs

It needs to specified to work regardless of where the listing is used.
E.g. blog.ejs for index.qmd, ../../blog.ejs for
posts/post-with-code/index.qmd. Using a project path doesn’t work:

_metadata.yml

listing:
  template: /blog.ejs

Reproduce the examples from the linked listings repository, starting with posts/post-with-code/index.qmd and _metadata.yml. Trace how listing contents and template paths are resolved; done means project-relative contents and templates work consistently from nested listings, with the reported warnings and path failures addressed.