Classify streaming rate-limit errors (#40931)

## What changed

- Classify `response.failed` events with the `rate_limit_exceeded` code as a distinct retryable error while preserving any parsed retry delay.
- Expose the error as `rateLimitExceeded` through the core protocol and app-server schemas after stream retries are exhausted.
- Preserve the upstream message for TUI display while keeping it out of telemetry summaries.

## Testing

- Cover SSE classification, retry metadata, protocol conversion and serialization, exhausted stream retries, telemetry redaction, and TUI rendering.

GitOrigin-RevId: 02dab4d3477dcd7653a58c49c4bd38687a616579

codex-rs/protocol/src/error.rs

@@ -91,6 +91,9 @@ pub enum CodexErrorDetails {
     /// The Session loop treats this as a transient error and will automatically retry the turn.
     #[error("stream disconnected before completion: {0}")]
     Stream(String),
+    /// A retryable upstream rate limit received inside the response stream.
+    #[error("rate limit exceeded: {0}")]
+    RateLimitExceeded(String),
     #[error(
         "Codex ran out of room in the model's context window. Start a new thread or clear earlier history before retrying."
     )]
@@ -388,6 +391,7 @@ impl CodexErr {
             | CodexErrorDetails::CyberPolicy { .. }
             | CodexErrorDetails::MisalignmentPolicyViolation { .. } => false,
             CodexErrorDetails::Stream(..)
+            | CodexErrorDetails::RateLimitExceeded(_)
             | CodexErrorDetails::Timeout
             | CodexErrorDetails::RequestTimeout
             | CodexErrorDetails::UnexpectedStatus(_)
@@ -424,6 +428,7 @@ impl CodexErr {
         match &self.details {
             CodexErrorDetails::ContextWindowExceeded => CodexErrorInfo::ContextWindowExceeded,
             CodexErrorDetails::SessionBudgetExceeded => CodexErrorInfo::SessionBudgetExceeded,
+            CodexErrorDetails::RateLimitExceeded(_) => CodexErrorInfo::RateLimitExceeded,
             CodexErrorDetails::UsageLimitReached(_)
             | CodexErrorDetails::QuotaExceeded
             | CodexErrorDetails::UsageNotIncluded => CodexErrorInfo::UsageLimitExceeded,