Move architecture and operating system probing to Python (#2381)

The architecture of uv does not necessarily match that of the python
interpreter (#2326). In cross compiling/testing scenarios the operating
system can also mismatch. To solve this, we move arch and os detection
to python, vendoring the relevant pypa/packaging code, preventing
mismatches between what the python interpreter was compiled for and what
uv was compiled for.

To make the scripts more manageable, they are now a directory in a
tempdir and we run them with `python -m` . I've simplified the
pypa/packaging code since we're still building the tags in rust. A
`Platform` is now instantiated by querying the python interpreter for
its platform. The pypa/packaging files are copied verbatim for easier
updates except a `lru_cache()` python 3.7 backport.

Error handling is done by a `"result": "success|error"` field that allow
passing error details to rust:

```console
$ uv venv --no-cache
  × Can't use Python at `/home/konsti/projects/uv/.venv/bin/python3`
  ╰─▶ Unknown operation system `linux`
```

I've used the [maturin sysconfig
collection](https://github.com/PyO3/maturin/tree/855f6d2cb1fb8fb43c2bb9e500ab0e5e84bd3140/sysconfig)
as reference. I'm unsure how to test these changes across the wide
variety of platforms.

Fixes #2326

crates/uv-interpreter/src/python_environment.rs

@@ -3,7 +3,6 @@ use std::path::{Path, PathBuf};
 
 use tracing::debug;
 
-use platform_host::Platform;
 use uv_cache::Cache;
 use uv_fs::{LockedFile, Simplified};
 
@@ -19,13 +18,13 @@ pub struct PythonEnvironment {
 
 impl PythonEnvironment {
     /// Create a [`PythonEnvironment`] for an existing virtual environment.
-    pub fn from_virtualenv(platform: Platform, cache: &Cache) -> Result<Self, Error> {
+    pub fn from_virtualenv(cache: &Cache) -> Result<Self, Error> {
         let Some(venv) = detect_virtual_env()? else {
             return Err(Error::VenvNotFound);
         };
         let venv = fs_err::canonicalize(venv)?;
         let executable = detect_python_executable(&venv);
-        let interpreter = Interpreter::query(&executable, platform, cache)?;
+        let interpreter = Interpreter::query(&executable, cache)?;
 
         debug_assert!(
             interpreter.base_prefix() == interpreter.base_exec_prefix(),
@@ -41,12 +40,8 @@ impl PythonEnvironment {
     }
 
     /// Create a [`PythonEnvironment`] for a Python interpreter specifier (e.g., a path or a binary name).
-    pub fn from_requested_python(
-        python: &str,
-        platform: &Platform,
-        cache: &Cache,
-    ) -> Result<Self, Error> {
-        let Some(interpreter) = find_requested_python(python, platform, cache)? else {
+    pub fn from_requested_python(python: &str, cache: &Cache) -> Result<Self, Error> {
+        let Some(interpreter) = find_requested_python(python, cache)? else {
             return Err(Error::RequestedPythonNotFound(python.to_string()));
         };
         Ok(Self {
@@ -56,8 +51,8 @@ impl PythonEnvironment {
     }
 
     /// Create a [`PythonEnvironment`] for the default Python interpreter.
-    pub fn from_default_python(platform: &Platform, cache: &Cache) -> Result<Self, Error> {
-        let interpreter = find_default_python(platform, cache)?;
+    pub fn from_default_python(cache: &Cache) -> Result<Self, Error> {
+        let interpreter = find_default_python(cache)?;
         Ok(Self {
             root: interpreter.prefix().to_path_buf(),
             interpreter,