## Summary
If you're developing on a package like `attrs` locally, and it has a
recursive extra like `attrs[dev]`, it turns out that we then try to find
the `attrs` in `attrs[dev]` from the registry, rather than recognizing
that it's part of the editable.
This PR fixes the issue by making editables slightly more first-class
throughout the resolver. Instead of mocking metadata, we explicitly
check for extras in various places. Part of the problem here is that we
treated editables as URL dependencies, but when we saw an _extra_ like
`attrs[dev]`, we didn't map that back to the URL. So now, we treat them
as registry dependencies, but with the appropriate guardrails
throughout.
Closes https://github.com/astral-sh/uv/issues/1447.
## Test Plan
- Cloned `attrs`.
- Ran `cargo run venv && cargo run pip install -e ".[dev]" -v`.
First, replace all usages in files in-place. I used my editor for this.
If someone wants to add a one-liner that'd be fun.
Then, update directory and file names:
```
# Run twice for nested directories
find . -type d -print0 | xargs -0 rename s/puffin/uv/g
find . -type d -print0 | xargs -0 rename s/puffin/uv/g
# Update files
find . -type f -print0 | xargs -0 rename s/puffin/uv/g
```
Then add all the files again
```
# Add all the files again
git add crates
git add python/uv
# This one needs a force-add
git add -f crates/uv-trampoline
```
