Rename to uv (#1302)

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
```

crates/uv-resolver/src/prerelease_mode.rs

@@ -0,0 +1,98 @@
+use rustc_hash::FxHashSet;
+
+use pep508_rs::{Requirement, VersionOrUrl};
+use uv_normalize::PackageName;
+
+#[derive(Debug, Default, Clone, Copy, PartialEq, Eq)]
+#[cfg_attr(feature = "clap", derive(clap::ValueEnum))]
+pub enum PreReleaseMode {
+    /// Disallow all pre-release versions.
+    Disallow,
+
+    /// Allow all pre-release versions.
+    Allow,
+
+    /// Allow pre-release versions if all versions of a package are pre-release.
+    IfNecessary,
+
+    /// Allow pre-release versions for first-party packages with explicit pre-release markers in
+    /// their version requirements.
+    Explicit,
+
+    /// Allow pre-release versions if all versions of a package are pre-release, or if the package
+    /// has an explicit pre-release marker in its version requirements.
+    #[default]
+    IfNecessaryOrExplicit,
+}
+
+/// Like [`PreReleaseMode`], but with any additional information required to select a candidate,
+/// like the set of direct dependencies.
+#[derive(Debug, Clone)]
+pub(crate) enum PreReleaseStrategy {
+    /// Disallow all pre-release versions.
+    Disallow,
+
+    /// Allow all pre-release versions.
+    Allow,
+
+    /// Allow pre-release versions if all versions of a package are pre-release.
+    IfNecessary,
+
+    /// Allow pre-release versions for first-party packages with explicit pre-release markers in
+    /// their version requirements.
+    Explicit(FxHashSet<PackageName>),
+
+    /// Allow pre-release versions if all versions of a package are pre-release, or if the package
+    /// has an explicit pre-release marker in its version requirements.
+    IfNecessaryOrExplicit(FxHashSet<PackageName>),
+}
+
+impl PreReleaseStrategy {
+    pub(crate) fn from_mode(mode: PreReleaseMode, direct_dependencies: &[Requirement]) -> Self {
+        match mode {
+            PreReleaseMode::Disallow => Self::Disallow,
+            PreReleaseMode::Allow => Self::Allow,
+            PreReleaseMode::IfNecessary => Self::IfNecessary,
+            PreReleaseMode::Explicit => Self::Explicit(
+                direct_dependencies
+                    .iter()
+                    .filter(|requirement| {
+                        let Some(version_or_url) = &requirement.version_or_url else {
+                            return false;
+                        };
+                        let version_specifiers = match version_or_url {
+                            VersionOrUrl::VersionSpecifier(version_specifiers) => {
+                                version_specifiers
+                            }
+                            VersionOrUrl::Url(_) => return false,
+                        };
+                        version_specifiers
+                            .iter()
+                            .any(pep440_rs::VersionSpecifier::any_prerelease)
+                    })
+                    .map(|requirement| requirement.name.clone())
+                    .collect(),
+            ),
+            PreReleaseMode::IfNecessaryOrExplicit => Self::IfNecessaryOrExplicit(
+                direct_dependencies
+                    .iter()
+                    .filter(|requirement| {
+                        let Some(version_or_url) = &requirement.version_or_url else {
+                            return false;
+                        };
+                        let version_specifiers = match version_or_url {
+                            VersionOrUrl::VersionSpecifier(version_specifiers) => {
+                                version_specifiers
+                            }
+                            VersionOrUrl::Url(_) => return false,
+                        };
+                        version_specifiers
+                            .iter()
+                            .any(pep440_rs::VersionSpecifier::any_prerelease)
+                    })
+                    .map(|requirement| requirement.name.clone())
+                    .collect(),
+            ),
+        }
+    }
+}