[codex-rs] enforce PAT workspace restrictions (#27450)

## Summary

- validate a hydrated personal access token's workspace against
`forced_chatgpt_workspace_id` before persisting `codex login
--with-access-token`
- apply the same PAT-only check when restricted auth managers load
environment, ephemeral, or persisted credentials
- enforce PAT workspace restrictions in the existing central
login-restriction path
- leave Agent Identity and cloud bootstrap behavior unchanged

## Scope

This is intentionally the small PAT-only change. It does not attempt the
broader auth-manager/bootstrap unification; that needs separate design
work.

## Validation

- `CARGO_INCREMENTAL=0 CARGO_TARGET_DIR=/tmp/codex-pat-target just test
-p codex-login -p codex-cli` (410 passed)
- `CARGO_INCREMENTAL=0 CARGO_TARGET_DIR=/tmp/codex-pat-target just fix
-p codex-login -p codex-cli`
- `just fmt`
- `git diff --check`

Context: https://openai.slack.com/archives/D0AUPLV03RQ/p1781138331548269

codex-rs/cli/src/login.rs

@@ -207,6 +207,7 @@ pub async fn run_login_with_access_token(
         &config.codex_home,
         &access_token,
         config.cli_auth_credentials_store_mode,
+        config.forced_chatgpt_workspace_id.as_deref(),
         Some(&config.chatgpt_base_url),
     )
     .await