Revert #5642 because this generates:

// GENERATED CODE! DO NOT MODIFY BY HAND!

// This file was generated by [ts-rs](https://github.com/Aleph-Alpha/ts-rs). Do not edit this file manually.

export type GetAccountResponse = Account | null;

But Account is unknown.

The unique use of #[ts(export)] on GetAccountResponse is also suspicious as are the changes to codex-rs/app-server-protocol/src/export.rs since the existing system has worked fine for quite some time.

Though a pure backout of #5642 puts things in a state where, as the PR noted, the following does not work:

cargo run -p codex-app-server-protocol --bin export -- --out DIR

So in addition to the backout, this PR adds:

#[derive(Serialize, Deserialize, Debug, Clone, PartialEq, JsonSchema, TS)]
#[serde(rename_all = "camelCase")]
pub struct GetAccountResponse {
    pub account: Account,
}

and changes GetAccount.response as follows:

-        response: Option<Account>,
+        response: GetAccountResponse,

making it consistent with other types.

With this change, I verified that both of the following work:

just codex generate-ts --out /tmp/somewhere
cargo run -p codex-app-server-protocol --bin export -- --out /tmp/somewhere-else

The generated TypeScript is as follows:

// GetAccountResponse.ts
import type { Account } from "./Account";

export type GetAccountResponse = { account: Account, };

and

// Account.ts
import type { PlanType } from "./PlanType";

export type Account = { "type": "ApiKey", api_key: string, } | { "type": "chatgpt", email: string | null, plan_type: PlanType, };

Though while the inconsistency between "type": "ApiKey" and "type": "chatgpt" is quite concerning, I'm not sure if that format is ever written to disk in any case, but @owenlin0, I would recommend looking into that.

Also, it appears that the types in codex-rs/protocol/src/account.rs are used exclusively by the app-server-protocol crate, so perhaps they should just be moved there?