fix (agents): classify empty-chunk stream failures as timeout

src/agents/pi-embedded-helpers/errors.ts

@@ -480,6 +480,10 @@ export function formatAssistantErrorText(
     return transientCopy;
   }
 
+  if (isTimeoutErrorMessage(raw)) {
+    return "LLM request timed out.";
+  }
+
   if (isBillingErrorMessage(raw)) {
     return formatBillingErrorMessage(opts?.provider);
   }
@@ -568,7 +572,13 @@ const ERROR_PATTERNS = {
     "usage limit",
   ],
   overloaded: [/overloaded_error|"type"\s*:\s*"overloaded_error"/i, "overloaded"],
-  timeout: ["timeout", "timed out", "deadline exceeded", "context deadline exceeded"],
+  timeout: [
+    "timeout",
+    "timed out",
+    "deadline exceeded",
+    "context deadline exceeded",
+    /without sending (?:any )?chunks?/i,
+  ],
   billing: [
     /["']?(?:status|code)["']?\s*[:=]\s*402\b|\bhttp\s*402\b|\berror(?:\s+code)?\s*[:=]?\s*402\b|\b(?:got|returned|received)\s+(?:a\s+)?402\b|^\s*402\s+payment/i,
     "payment required",