python: Init venv/virtualenv activation scripts during list/resolve (#40816)

This means that existence of activation scripts for venv/virtualenv will
be checked locally either on the host if editing locally, or the remote
by the remote proxy if editing a remote project.

Closes https://github.com/zed-industries/zed/issues/40263

Release Notes:

- N/A

crates/util/src/shell.rs

@@ -1,6 +1,7 @@
+use serde::{Deserialize, Serialize};
 use std::{borrow::Cow, fmt, path::Path, sync::LazyLock};
 
-#[derive(Debug, Default, Clone, Copy, PartialEq, Eq, Hash)]
+#[derive(Debug, Default, Clone, Copy, PartialEq, Eq, Hash, Serialize, Deserialize)]
 pub enum ShellKind {
     #[default]
     Posix,