Honor server retry advice across Responses retries and fallback (#49441)

## Why

Responses overload and exhausted-request errors could terminate despite server retry advice, and WebSocket-to-HTTP fallback could issue a request before the advised deadline.

## What changed

- Allow `ServerOverloaded` and `RetryLimit` errors to retry when server advice is present, within the configured retry budgets.
- Preserve `Retry-After` headers from rejected WebSocket upgrades and wait for the server deadline before falling back to HTTP.
- Keep quota, usage-limit, and policy failures terminal even when they include retry advice.

## Testing

Add coverage for HTTP overload and rate-limit recovery, WebSocket upgrade rejection and fallback timing, retry deadline preservation through error mapping, and retry limits for sampling and manual and automatic compaction.

GitOrigin-RevId: 72d30a9f078652664754dfa971fd7dc7a78f20e8

codex-rs/protocol/src/error.rs

@@ -403,18 +403,19 @@ impl CodexErr {
             | CodexErrorDetails::UnsupportedOperation(_)
             | CodexErrorDetails::Sandbox(_)
             | CodexErrorDetails::LandlockSandboxExecutableNotProvided
-            | CodexErrorDetails::RetryLimit(_)
             | CodexErrorDetails::ContextWindowExceeded
             | CodexErrorDetails::ThreadNotFound(_)
             | CodexErrorDetails::AgentLimitReached { .. }
             | CodexErrorDetails::Spawn
             | CodexErrorDetails::SessionConfiguredNotFirstEvent
             | CodexErrorDetails::UsageLimitReached(_)
-            | CodexErrorDetails::ServerOverloaded
             | CodexErrorDetails::FlexUnavailable
             | CodexErrorDetails::CyberPolicy { .. }
             | CodexErrorDetails::BioPolicy { .. }
             | CodexErrorDetails::MisalignmentPolicyViolation { .. } => None,
+            CodexErrorDetails::ServerOverloaded | CodexErrorDetails::RetryLimit(_) => {
+                self.server_retry_delay()
+            }
             CodexErrorDetails::Stream(..)
             | CodexErrorDetails::ContentFilter
             | CodexErrorDetails::RateLimitExceeded(_)