Better usage errors (#1941)

<img width="771" height="279" alt="image"
src="https://github.com/user-attachments/assets/e56f967f-bcd7-49f7-8a94-3d88df68b65a"
/>

codex-rs/core/src/codex.rs

@@ -1290,6 +1290,7 @@ async fn run_turn(
             Ok(output) => return Ok(output),
             Err(CodexErr::Interrupted) => return Err(CodexErr::Interrupted),
             Err(CodexErr::EnvVar(var)) => return Err(CodexErr::EnvVar(var)),
+            Err(e @ (CodexErr::UsageLimitReached | CodexErr::UsageNotIncluded)) => return Err(e),
             Err(e) => {
                 // Use the configured provider-specific stream retry budget.
                 let max_retries = sess.client.get_provider().stream_max_retries();