test: harden sandbox policy mapping across switch states

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

tests/test_tui.py

@@ -1964,3 +1964,22 @@ async def test_jk_typed_into_input_is_literal():
         await pilot.pause()
         assert nickname.value == "jk"
         assert app.focused is nickname
+
+
+def test_policy_is_none_when_sandbox_off_regardless_of_suboptions():
+    """When sandboxing is off, the (now hidden) fs/net sub-option values are
+    discarded — the submitted policy is None no matter what they hold."""
+    from hqt.tui.screens.new_session import NewSessionScreen
+
+    assert NewSessionScreen._policy_from(False, "ro", False) is None
+    assert NewSessionScreen._policy_from(False, "rw", True) is None
+
+
+def test_policy_reflects_suboptions_when_sandbox_on():
+    """When sandboxing is on, the fs/net sub-option values flow into the policy."""
+    from hqt.tui.screens.new_session import NewSessionScreen
+
+    policy = NewSessionScreen._policy_from(True, "ro", False)
+    assert policy is not None
+    assert policy.fs == "ro"
+    assert policy.net is False