This way we don't error-out when a path is a directory. That said, we're
still only including the root in sidx.db (e.g. manifests/ but not
manifests/*.json). We should change that next.
Also renamed "blob_id" to "blake3_id" because datasette has a special
branch for ${column}_id referencing a table that contains ${column}
First attempt at both Rust and snix-castore.
I'll start by putting together a single-file CLI app,
no splitting modules out until needed, no separation of concerns.
Currently, just the fetching is implemented:
```
$ sidx pkgs/dev*/cuda-*/cuda/manifests/*.json
```
npins: init
