chore(deps): 🔧 move benchmark-only dependencies to a bench group

benches/README.md

@@ -10,3 +10,9 @@ different SRC variants. They are grouped by the kind of workload exercised:
 - [`stack/`](stack/) — One-shot SRC over stacks of trains against sequential
   pairwise application, by stack depth: accuracy against dense references and
   wall time. See [`stack/README.md`](stack/README.md).
+
+The scripts need the `bench` dependency group (included in `dev`):
+
+```bash
+uv sync --group bench
+```

pyproject.toml

@@ -64,15 +64,19 @@ test = [
   "pytest>=9.1.0,<10.0",
   "pytest-benchmark>=5.2.3",
   "quimb>=1.14.0,<2",
+  # Not imported directly: without it, cotengra (via quimb) warns when it plans a
+  # contraction, which `filterwarnings = ["error"]` turns into a failure.
   "cmaes>=0.12.0",
 ]
+# Only the scripts under benches/ need these.
+bench = ["cyclopts>=3.20", "quimb>=1.14.0,<2", "cmaes>=0.12.0", "scipy"]
 dev = [
   "scalene",
   "prek>=0.2.6",
   "ruff==0.16.9",
-  "cyclopts>=3.20",
   "ty==0.0.82",
   { include-group = "test" },
+  { include-group = "bench" },
 ]
 interactive = [
   "ipykernel>=7.2.0",