surface stage failures instead of printing rc

kaggle/notebook_finish.py

@@ -53,10 +53,14 @@ def main() -> None:
     print("== export + quantise ==", flush=True)
     rc = run("export")
     print("export rc", rc)
+    if rc != 0:
+        raise SystemExit("export/quantise failed")
 
     print("== eval ==", flush=True)
     rc = run("eval", {"EVAL_VOICES": EVAL_VOICES})
     print("eval rc", rc)
+    if rc != 0:
+        raise SystemExit("eval failed")
 
 
 if __name__ == "__main__":