Rename to uv

[zanieb]

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

[zanieb]

To make my life easier, merged with:

git merge main -X theirs

Then replaced all the "new" "Puffin" usages with "uv".

Then repaired some duplicated imports.