fix: robust Retry-After extraction across provider backends

nanobot/providers/openai_compat_provider.py

@@ -571,9 +571,14 @@ class OpenAICompatProvider(LLMProvider):
 
     @staticmethod
     def _handle_error(e: Exception) -> LLMResponse:
-        body = getattr(e, "doc", None) or getattr(getattr(e, "response", None), "text", None)
-        msg = f"Error: {body.strip()[:500]}" if body and body.strip() else f"Error calling LLM: {e}"
-        return LLMResponse(content=msg, finish_reason="error")
+        response = getattr(e, "response", None)
+        body = getattr(e, "doc", None) or getattr(response, "text", None)
+        body_text = str(body).strip() if body is not None else ""
+        msg = f"Error: {body_text[:500]}" if body_text else f"Error calling LLM: {e}"
+        retry_after = LLMProvider._extract_retry_after_from_headers(getattr(response, "headers", None))
+        if retry_after is None:
+            retry_after = LLMProvider._extract_retry_after(msg)
+        return LLMResponse(content=msg, finish_reason="error", retry_after=retry_after)
 
     # ------------------------------------------------------------------
     # Public API
@@ -646,4 +651,4 @@ class OpenAICompatProvider(LLMProvider):
             return self._handle_error(e)
 
     def get_default_model(self) -> str:
-        return self.default_model
+        return self.default_model