Preserve usage limit windows in turn and compaction analytics (#48174)

## Why

Usage limit errors discarded the server-selected window responsible for the limit, leaving turn and compaction analytics unable to distinguish five-hour limits from weekly limits.

## What changed

Preserve optional `limit_window_minutes` from usage limit error responses in `UsageLimitReachedError` and report it as `usage_limit_window_minutes` in turn and compaction events. Accept unsigned integers that fit in `u16`; treat missing, null, malformed, or out-of-range values as unknown. Events for other error kinds report `null`.

## Testing

Add coverage for HTTP and wrapped WebSocket error mapping, analytics serialization and reduction, and app-server propagation to turn and local/remote compaction events. Cases include five-hour and weekly windows, missing or invalid values, and unrelated errors.

GitOrigin-RevId: a32066a007559d91a3c868a756bfd0f976777176

codex-rs/protocol/src/error.rs

@@ -676,6 +676,8 @@ impl std::fmt::Display for RetryLimitReachedError {
 pub struct UsageLimitReachedError {
     pub plan_type: Option<PlanType>,
     pub resets_at: Option<DateTime<Utc>>,
+    /// Server-selected window responsible for the limit, in minutes.
+    pub limit_window_minutes: Option<u16>,
     pub rate_limits: Option<Box<RateLimitSnapshot>>,
     pub promo_message: Option<String>,
     pub rate_limit_reached_type: Option<RateLimitReachedType>,