fix: cool down Sub2API large context upstream failures

scripts/platform-infra-sub2api-codex-routing-contract-test.ts

@@ -48,6 +48,11 @@ if (parsed.pool?.defaultTempUnschedulable?.enabled === true) {
   const gateway502Rule = rules.find((rule) => rule.statusCode === 502);
   const gateway502Keywords = new Set((gateway502Rule?.keywords ?? []).map((keyword) => keyword.toLowerCase()));
   assertCondition(gateway502Keywords.has("recovered upstream error"), "502 temporary-unschedulable rule must catch recovered upstream error wrappers", gateway502Rule);
+  const largeContext413Rule = rules.find((rule) => rule.statusCode === 413);
+  const largeContext413Keywords = new Set((largeContext413Rule?.keywords ?? []).map((keyword) => keyword.toLowerCase()));
+  for (const keyword of ["openai_error", "context length", "maximum context"]) {
+    assertCondition(largeContext413Keywords.has(keyword), "413 temporary-unschedulable rule must catch large-context upstream failures", { keyword, largeContext413Rule });
+  }
   const gateway504Rule = rules.find((rule) => rule.statusCode === 504);
   const gateway504Keywords = new Set((gateway504Rule?.keywords ?? []).map((keyword) => keyword.toLowerCase()));
   for (const keyword of ["gateway timeout", "unknown error", "context deadline exceeded"]) {
@@ -78,6 +83,7 @@ console.log(JSON.stringify({
     "optional WebSocket mode overrides use supported values",
     "temporary unschedulable rules are structurally valid when enabled",
     "generic recovered upstream error wrappers are caught by cooldown rules",
+    "large-context upstream failures are caught by the 413 cooldown rule",
     "gateway timeout wrappers are caught by the 504 cooldown rule",
     "Codex weekly-limit prompts are caught by account-state and quota cooldown rules",
     "upstream model-routing failures are caught by the 503 cooldown rule",