Problem:
Fallback pynvim version lookup is broken since Vimscript-to-Lua rewrite.
- `vim.fs.basename()` returns the module filename instead of the
directory needed to discover adjacent metadata. This produces an
empty metadata list, hiding the remaining issues.
- `table.sort()` requires a Boolean comparator, while
`vim.version.cmp()` returns a number.
- `table.sort()` sorts in place and returns no value, so assigning its
result discards the metadata list.
Solution:
- Use `vim.fs.dirname()` to discover adjacent package metadata.
- Use `vim.version.gt()` as the descending Boolean comparator.
- Sort the metadata list in place.
This restores fallback version detection when `neovim.VERSION` is
unavailable.
3ea7bc3f60