test(builder): version-robust layout-error match

why: tmux's invalid-layout error wording varies by version — "invalid
layout: not-a-layout" on 3.7 versus "select-layout: can't set layout:
not-a-layout" on 3.2a — so the strict "invalid layout" match passed
local 3.7 but failed CI on tmux 3.2a.

what:
- Match the rejected layout name "not-a-layout" (echoed by both
  versions) in test_synchronize_restores_state_when_pane_setup_aborts

Author: tony

tests/workspace/test_builder.py

@@ -2325,7 +2325,10 @@ def after_window_finished(self, window: Window) -> None:
             plugins=plugins,
         )
 
-        with pytest.raises(LibTmuxException, match="invalid layout"):
+        # tmux's invalid-layout wording varies by version ("invalid layout:
+        # not-a-layout" on 3.7, "select-layout: can't set layout: not-a-layout"
+        # on 3.2a), so match the rejected layout name both versions echo.
+        with pytest.raises(LibTmuxException, match="not-a-layout"):
             builder.build(session=session)
 
         window = session.windows[0]