Allow creating venv with free-threaded python builds (#7431)

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## Summary

closes #4828

First iteration for an implementation. I need to add more tests but
wanted your opinion on the implementation first.

<!-- What's the purpose of the change? What does it do, and why? -->

## Test Plan
Currently tested using the following command but will add tests shortly:

```console
D:\repo\uv> cargo run venv -p 3.13t && .venv\Scripts\python.exe
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 0.52s
     Running `target\debug\uv.exe venv -p 3.13t`
Using Python 3.13.0rc1 interpreter at: C:\Users\bschoen\AppData\Local\Programs\Python\Python313\python3.13t.exe
Creating virtualenv at: .venv
Activate with: .venv\Scripts\activate
Python 3.13.0rc1 experimental free-threading build (tags/v3.13.0rc1:e4a3e78, Jul 31 2024, 21:06:58) [MSC v.1940 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> 
```

---------

Co-authored-by: Zanie Blue <contact@zanie.dev>

crates/uv-virtualenv/src/virtualenv.rs

@@ -481,19 +481,20 @@ impl WindowsExecutable {
     }
 
     /// The name of the launcher shim.
-    fn launcher(self) -> &'static str {
+    fn launcher(self, interpreter: &Interpreter) -> &'static str {
         match self {
-            WindowsExecutable::Python => "venvlauncher.exe",
-            WindowsExecutable::PythonMajor => "venvlauncher.exe",
-            WindowsExecutable::PythonMajorMinor => "venvlauncher.exe",
-            WindowsExecutable::Pythonw => "venvwlauncher.exe",
+            Self::Python | Self::PythonMajor | Self::PythonMajorMinor
+                if interpreter.gil_disabled() =>
+            {
+                "venvlaunchert.exe"
+            }
+            Self::Python | Self::PythonMajor | Self::PythonMajorMinor => "venvlauncher.exe",
+            Self::Pythonw if interpreter.gil_disabled() => "venvwlaunchert.exe",
+            Self::Pythonw => "venvwlauncher.exe",
             // From 3.13 on these should replace the `python.exe` and `pythonw.exe` shims.
             // These are not relevant as of now for PyPy as it doesn't yet support Python 3.13.
-            WindowsExecutable::PyPy => "venvlauncher.exe",
-            WindowsExecutable::PyPyMajor => "venvlauncher.exe",
-            WindowsExecutable::PyPyMajorMinor => "venvlauncher.exe",
-            WindowsExecutable::PyPyw => "venvwlauncher.exe",
-            WindowsExecutable::PyPyMajorMinorw => "venvwlauncher.exe",
+            Self::PyPy | Self::PyPyMajor | Self::PyPyMajorMinor => "venvlauncher.exe",
+            Self::PyPyw | Self::PyPyMajorMinorw => "venvwlauncher.exe",
             WindowsExecutable::GraalPy => "venvlauncher.exe",
         }
     }
@@ -534,7 +535,7 @@ fn copy_launcher_windows(
         .join("venv")
         .join("scripts")
         .join("nt")
-        .join(executable.launcher());
+        .join(executable.launcher(interpreter));
     match fs_err::copy(shim, scripts.join(executable.exe(interpreter))) {
         Ok(_) => return Ok(()),
         Err(err) if err.kind() == io::ErrorKind::NotFound => {}
@@ -545,7 +546,7 @@ fn copy_launcher_windows(
 
     // Third priority: on Conda at least, we can look for the launcher shim next to
     // the Python executable itself.
-    let shim = base_python.with_file_name(executable.launcher());
+    let shim = base_python.with_file_name(executable.launcher(interpreter));
     match fs_err::copy(shim, scripts.join(executable.exe(interpreter))) {
         Ok(_) => return Ok(()),
         Err(err) if err.kind() == io::ErrorKind::NotFound => {}