Update cargo to 2024 edition (#842)

Some effects of this change:
- New formatting changes across many files. No functionality changes
should occur from that.
- Calls to `set_env` are considered unsafe, since this only happens in
tests we wrap them in `unsafe` blocks

codex-rs/mcp-types/src/lib.rs

@@ -5,9 +5,9 @@
 // ```shell
 // ./generate_mcp_types.py
 // ```
-use serde::de::DeserializeOwned;
 use serde::Deserialize;
 use serde::Serialize;
+use serde::de::DeserializeOwned;
 use std::convert::TryFrom;
 
 pub const MCP_SCHEMA_VERSION: &str = "2025-03-26";