check for updates (#1764)

1. Ping https://api.github.com/repos/openai/codex/releases/latest (at
most once every 20 hrs)
2. Store the result in ~/.codex/version.jsonl
3. If CARGO_PKG_VERSION < latest_version, print a message at boot.

---------

Co-authored-by: easong-openai <easong@openai.com>

codex-cli/bin/codex.js

@@ -83,6 +83,7 @@ if (wantsNative && process.platform !== 'win32') {
 
   const child = spawn(binaryPath, process.argv.slice(2), {
     stdio: "inherit",
+    env: { ...process.env, CODEX_MANAGED_BY_NPM: "1" },
   });
 
   child.on("error", (err) => {