fix: clarify pending admission failure outcome (#101)

tests/test_issue_101.py

@@ -139,6 +139,7 @@ def test_partial_recovery_frees_admission_and_keeps_pending_order(
     )
     assert partial["ok"] is False
     assert acquired is True, partial
+    assert "no new observation acquired" not in partial["error"]
 
     with sqlite3.connect(store_path) as conn:
         assert conn.execute(