fix(claude): use cleanup-tolerant temporary directory

tests/test_claude_backend_tempdir.py

@@ -0,0 +1,59 @@
+"""Regression coverage for Claude CLI temporary-directory cleanup."""
+from __future__ import annotations
+
+import json
+import os
+import shutil
+import tempfile
+from types import SimpleNamespace
+
+from skillopt.model import claude_backend
+
+
+def test_claude_print_uses_cleanup_tolerant_temporary_directory(monkeypatch) -> None:
+    cleanup_modes = []
+    subprocess_cwd = ""
+
+    def simulated_windows_rmtree(cls, name, ignore_errors=False, repeated=False):
+        del cls, repeated
+        cleanup_modes.append(ignore_errors)
+        if not ignore_errors:
+            raise PermissionError(32, "directory is still in use", name)
+        shutil.rmtree(name, ignore_errors=True)
+
+    def fake_run(*args, **kwargs):
+        nonlocal subprocess_cwd
+        subprocess_cwd = kwargs["cwd"]
+        payload = {
+            "type": "result",
+            "result": "ok",
+            "usage": {"input_tokens": 2, "output_tokens": 3},
+        }
+        return SimpleNamespace(
+            returncode=0,
+            stdout=json.dumps(payload) + "\n",
+            stderr="",
+        )
+
+    monkeypatch.setattr(
+        tempfile.TemporaryDirectory,
+        "_rmtree",
+        classmethod(simulated_windows_rmtree),
+    )
+    monkeypatch.setattr(claude_backend.subprocess, "run", fake_run)
+
+    text, _, usage = claude_backend._run_claude_print(
+        system="system",
+        prompt="prompt",
+        model="",
+        tools=None,
+        tool_choice=None,
+        return_message=False,
+        timeout=10,
+    )
+
+    assert text == "ok"
+    assert usage == {"prompt_tokens": 2, "completion_tokens": 3, "total_tokens": 5}
+    assert cleanup_modes == [True]
+    assert subprocess_cwd
+    assert not os.path.exists(subprocess_cwd)