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/app-server-protocol/src/protocol/v2/shared.rs

@@ -78,6 +78,7 @@ pub enum CodexErrorInfo {
     ContextWindowExceeded,
     SessionBudgetExceeded,
     UsageLimitExceeded,
+    RateLimitExceeded,
     ServerOverloaded,
     CyberPolicy,
     MisalignmentPolicyViolation,
@@ -125,6 +126,7 @@ impl From<CoreCodexErrorInfo> for CodexErrorInfo {
             CoreCodexErrorInfo::ContextWindowExceeded => CodexErrorInfo::ContextWindowExceeded,
             CoreCodexErrorInfo::SessionBudgetExceeded => CodexErrorInfo::SessionBudgetExceeded,
             CoreCodexErrorInfo::UsageLimitExceeded => CodexErrorInfo::UsageLimitExceeded,
+            CoreCodexErrorInfo::RateLimitExceeded => CodexErrorInfo::RateLimitExceeded,
             CoreCodexErrorInfo::ServerOverloaded => CodexErrorInfo::ServerOverloaded,
             CoreCodexErrorInfo::CyberPolicy => CodexErrorInfo::CyberPolicy,
             CoreCodexErrorInfo::MisalignmentPolicyViolation => {