fix: address code review findings

- failover-policy.test.ts: move 4 new it() blocks inside describe()
  (they were orphaned outside the block and would not execute)
- run.ts: add idleTimedOut to the assistantFailoverDecision call site
  (missing required field caused TypeScript error and reproduced the freeze
  for the initial-decision code path in the outer loop)
- assistant-failover.ts: treat idleTimedOut same as timedOut in
  markFailedProfile to avoid incorrect profile failure recording
- assistant-failover.ts: add warn log when idle timeout rotates a profile
- assistant-failover.ts: extend resolveAssistantFailoverErrorMessage to
  accept idleTimedOut so surface_error emits "LLM request timed out."
  instead of the generic "LLM request failed."

src/agents/pi-embedded-runner/run.ts

@@ -2355,6 +2355,7 @@ export async function runEmbeddedPiAgent(
             failoverFailure,
             failoverReason: assistantFailoverReason,
             timedOut,
+            idleTimedOut,
             timedOutDuringCompaction,
             timedOutDuringToolExecution,
             profileRotated: false,

src/agents/pi-embedded-runner/run/assistant-failover.ts

@@ -98,7 +98,8 @@ export async function handleAssistantFailover(params: {
 
   if (decision.action === "rotate_profile") {
     const failedProfileId = params.lastProfileId;
-    const failureReason = params.timedOut ? "timeout" : params.assistantProfileFailureReason;
+    const failureReason =
+      params.timedOut || params.idleTimedOut ? "timeout" : params.assistantProfileFailureReason;
     const markFailedProfile = async () => {
       if (!failedProfileId || !failureReason || failureReason === "timeout") {
         return;
@@ -157,6 +158,9 @@ export async function handleAssistantFailover(params: {
     if (params.timedOut && !params.isProbeSession && failedProfileId) {
       params.warn(`Profile ${failedProfileId} timed out. Trying next account...`);
     }
+    if (params.idleTimedOut && !params.isProbeSession && failedProfileId) {
+      params.warn(`Profile ${failedProfileId} idle timeout (model silent). Trying next account...`);
+    }
     if (params.cloudCodeAssistFormatError && failedProfileId) {
       params.warn(
         `Profile ${failedProfileId} hit Cloud Code Assist format error. Tool calls will be sanitized on retry.`,
@@ -280,6 +284,7 @@ function resolveAssistantFailoverErrorMessage(params: {
   sessionKey?: string;
   activeErrorContext: { provider: string; model: string };
   timedOut: boolean;
+  idleTimedOut: boolean;
   rateLimitFailure: boolean;
   billingFailure: boolean;
   authFailure: boolean;
@@ -294,7 +299,7 @@ function resolveAssistantFailoverErrorMessage(params: {
         })
       : undefined) ||
     params.lastAssistant?.errorMessage?.trim() ||
-    (params.timedOut
+    (params.timedOut || params.idleTimedOut
       ? "LLM request timed out."
       : params.rateLimitFailure
         ? "LLM request rate limited."

src/agents/pi-embedded-runner/run/failover-policy.test.ts

@@ -127,6 +127,7 @@ describe("resolveRunFailoverDecision", () => {
         failoverFailure: true,
         failoverReason: "format",
         timedOut: false,
+        idleTimedOut: false,
         timedOutDuringCompaction: false,
         timedOutDuringToolExecution: false,
         profileRotated: false,
@@ -148,6 +149,7 @@ describe("resolveRunFailoverDecision", () => {
         failoverFailure: true,
         failoverReason: "format",
         timedOut: false,
+        idleTimedOut: false,
         timedOutDuringCompaction: false,
         timedOutDuringToolExecution: false,
         profileRotated: false,
@@ -297,7 +299,6 @@ describe("resolveRunFailoverDecision", () => {
       reason: null,
     });
   });
-});
 
   it("rotates profile on LLM idle timeout before falling back", () => {
     // idleTimedOut = model produced no tokens; no provider API error was classified.