fix: fail stale codex thread resume

src/backend/codex-stdio.ts

@@ -452,9 +452,7 @@ async function runCodexStdioTurnWithSession(options: CodexStdioTurnOptions, sess
         emitEvent({ type: "backend_status", payload: { phase: "thread/resume:completed", threadId } });
       } catch (error) {
         const failure = normalizeFailure(error);
-        if (!isMissingRolloutThreadResumeFailure(failure)) throw error;
-        emitEvent({ type: "backend_status", payload: threadResumeNonResumablePayload(options.threadId, failure) });
-        threadId = await startThread("thread/replacement-start");
+        throw threadResumeFailure(options.threadId, failure);
       }
     } else {
       threadId = await startThread();
@@ -910,12 +908,6 @@ function normalizeFailure(error: unknown): CodexStdioFailure {
   return new CodexStdioFailure(classifyMessageFailureKind(message, "backend-protocol-error"), message, "codex-stdio");
 }
 
-function isMissingRolloutThreadResumeFailure(error: CodexStdioFailure): boolean {
-  if (error.phase !== "response:thread/resume") return false;
-  const text = `${error.message}\n${JSON.stringify(error.details)}`.toLowerCase();
-  return text.includes("no rollout found for thread id");
-}
-
 function threadResumeFailure(threadId: string, error: CodexStdioFailure): CodexStdioFailure {
   return new CodexStdioFailure(
     "thread-resume-failed",
@@ -931,18 +923,6 @@ function threadResumeFailure(threadId: string, error: CodexStdioFailure): CodexS
   );
 }
 
-function threadResumeNonResumablePayload(threadId: string, error: CodexStdioFailure): JsonRecord {
-  return {
-    phase: "thread/resume:non-resumable",
-    requestedThreadId: threadId,
-    originalFailureKind: error.failureKind,
-    originalPhase: error.phase,
-    originalDetails: redactJson(error.details),
-    replacement: "thread/start",
-    valuesPrinted: false,
-  };
-}
-
 function classifyCodexErrorRecord(error: JsonRecord, fallback: FailureKind): FailureKind {
   const parts: string[] = [];
   if (typeof error.message === "string") parts.push(error.message);