fix: use claude-3-haiku for validation ping; guard error.get() against string body from proxies

custom_components/anthropic_custom/config_flow.py

@@ -110,7 +110,7 @@ async def validate_input(hass: HomeAssistant, data: dict[str, Any]) -> None:
         if exc.status_code == 404:
             # Proxy does not support models endpoint — validate via a tiny messages call
             await client.messages.create(
-                model="claude-haiku-4-5",
+                model="claude-3-haiku-20240307",
                 max_tokens=1,
                 messages=[{"role": "user", "content": "hi"}],
                 timeout=10.0,
@@ -184,12 +184,13 @@ class AnthropicConfigFlow(ConfigFlow, domain=DOMAIN):
                 errors["base"] = "cannot_connect"
             except anthropic.APIStatusError as e:
                 errors["base"] = "unknown"
-                if (
-                    isinstance(e.body, dict)
-                    and (error := e.body.get("error"))
-                    and error.get("type") == "authentication_error"
-                ):
-                    errors["base"] = "authentication_error"
+                try:
+                    body = e.body if isinstance(e.body, dict) else {}
+                    error = body.get("error")
+                    if isinstance(error, dict) and error.get("type") == "authentication_error":
+                        errors["base"] = "authentication_error"
+                except Exception:
+                    pass
             except Exception:
                 _LOGGER.exception("Unexpected exception")
                 errors["base"] = "unknown"