Add codex apply to apply a patch created from the Codex remote agent (#1528)

In order to to this, I created a new `chatgpt` crate where we can put
any code that interacts directly with ChatGPT as opposed to the OpenAI
API. I added a disclaimer to the README for it that it should primarily
be modified by OpenAI employees.


https://github.com/user-attachments/assets/bb978e33-d2c9-4d8e-af28-c8c25b1988e8

codex-rs/chatgpt/src/chatgpt_token.rs

@@ -0,0 +1,24 @@
+use std::path::Path;
+use std::sync::LazyLock;
+use std::sync::RwLock;
+
+use codex_login::TokenData;
+
+static CHATGPT_TOKEN: LazyLock<RwLock<Option<TokenData>>> = LazyLock::new(|| RwLock::new(None));
+
+pub fn get_chatgpt_token_data() -> Option<TokenData> {
+    CHATGPT_TOKEN.read().ok()?.clone()
+}
+
+pub fn set_chatgpt_token_data(value: TokenData) {
+    if let Ok(mut guard) = CHATGPT_TOKEN.write() {
+        *guard = Some(value);
+    }
+}
+
+/// Initialize the ChatGPT token from auth.json file
+pub async fn init_chatgpt_token_from_auth(codex_home: &Path) -> std::io::Result<()> {
+    let auth_json = codex_login::try_read_auth_json(codex_home).await?;
+    set_chatgpt_token_data(auth_json.tokens.clone());
+    Ok(())
+}