Install versioned Python executables into the bin directory during uv python install (#8458)

Updates `uv python install` to link `python3.x` in the executable
directory (i.e., `~/.local/bin`) to the the managed interpreter path.

Includes

- #8569 
- #8571 

Remaining work

- #8663 
- #8650 
- Add an opt-out setting and flag
- Update documentation

crates/uv-python/src/installation.rs

@@ -305,6 +305,17 @@ impl PythonInstallationKey {
     pub fn libc(&self) -> &Libc {
         &self.libc
     }
+
+    /// Return a canonical name for a versioned executable.
+    pub fn versioned_executable_name(&self) -> String {
+        format!(
+            "python{maj}.{min}{var}{exe}",
+            maj = self.major,
+            min = self.minor,
+            var = self.variant.suffix(),
+            exe = std::env::consts::EXE_SUFFIX
+        )
+    }
 }
 
 impl fmt::Display for PythonInstallationKey {