## Summary
This PR adds support for pip's `--no-build-isolation`. When enabled,
build requirements won't be installed during PEP 517-style builds, but
the source environment _will_ be used when executing the build steps
themselves.
Closes https://github.com/astral-sh/uv/issues/1715.
## Summary
`PythonPlatform` only exists to format paths to directories within
virtual environments based on a root and an OS, so it's now
`VirtualenvLayout`.
`Virtualenv` is now used for non-virtual environment Pythons, so it's
now `PythonEnvironment`.
Address a few pedantic lints
lints are separated into separate commits so they can be reviewed
individually.
I've not added enforcement for any of these lints, but that could be
added if desirable.
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
```
