Added MCP server command to enable authentication using ChatGPT (#2373)

This PR adds two new APIs for the MCP server: 1) loginChatGpt, and 2)
cancelLoginChatGpt. The first starts a login server and returns a local
URL that allows for browser-based authentication, and the second
provides a way to cancel the login attempt. If the login attempt
succeeds, a notification (in the form of an event) is sent to a
subscriber.

I also added a timeout mechanism for the existing login server. The
loginChatGpt code path uses a 10-minute timeout by default, so if the
user fails to complete the login flow in that timeframe, the login
server automatically shuts down. I tested the timeout code by manually
setting the timeout to a much lower number and confirming that it works
as expected when used e2e.

codex-rs/mcp-server/Cargo.toml

@@ -18,6 +18,7 @@ workspace = true
 anyhow = "1"
 codex-arg0 = { path = "../arg0" }
 codex-core = { path = "../core" }
+codex-login = { path = "../login" }
 mcp-types = { path = "../mcp-types" }
 schemars = "0.8.22"
 serde = { version = "1", features = ["derive"] }