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/cli/src/linux-sandbox/main.rs

@@ -7,9 +7,9 @@ fn main() -> anyhow::Result<()> {
 #[cfg(target_os = "linux")]
 fn main() -> anyhow::Result<()> {
     use clap::Parser;
+    use codex_cli::LandlockCommand;
     use codex_cli::create_sandbox_policy;
     use codex_cli::landlock;
-    use codex_cli::LandlockCommand;
 
     let LandlockCommand {
         full_auto,

codex-rs/cli/src/main.rs

@@ -1,9 +1,9 @@
 use clap::Parser;
+use codex_cli::LandlockCommand;
+use codex_cli::SeatbeltCommand;
 use codex_cli::create_sandbox_policy;
 use codex_cli::proto;
 use codex_cli::seatbelt;
-use codex_cli::LandlockCommand;
-use codex_cli::SeatbeltCommand;
 use codex_exec::Cli as ExecCli;
 use codex_tui::Cli as TuiCli;
 

codex-rs/cli/src/proto.rs

@@ -1,9 +1,9 @@
 use std::io::IsTerminal;
 
 use clap::Parser;
+use codex_core::Codex;
 use codex_core::protocol::Submission;
 use codex_core::util::notify_on_sigint;
-use codex_core::Codex;
 use tokio::io::AsyncBufReadExt;
 use tokio::io::BufReader;
 use tracing::error;