Window(feat): add next_layout, previous_layout wrapping real tmux commands

why: next-layout and previous-layout are real tmux commands (since 1.0)
with their own cmd_entry structs. Invoke them directly instead of routing
through select-layout flags.
what:
- Add Window.next_layout() calling tmux next-layout directly
- Add Window.previous_layout() calling tmux previous-layout directly
- Add tests verifying layout changes and round-trip cycling

Author: tony

src/libtmux/window.py

@@ -496,6 +496,50 @@ def select_layout(
 
         return self
 
+    def next_layout(self) -> Window:
+        """Cycle to the next layout via ``$ tmux next-layout``.
+
+        Returns
+        -------
+        :class:`Window`
+            Self, for method chaining.
+
+        Examples
+        --------
+        >>> pane1 = window.active_pane
+        >>> pane2 = window.split()
+        >>> window.next_layout()
+        Window(...)
+        """
+        proc = self.cmd("next-layout")
+
+        if proc.stderr:
+            raise exc.LibTmuxException(proc.stderr)
+
+        return self
+
+    def previous_layout(self) -> Window:
+        """Cycle to the previous layout via ``$ tmux previous-layout``.
+
+        Returns
+        -------
+        :class:`Window`
+            Self, for method chaining.
+
+        Examples
+        --------
+        >>> pane1 = window.active_pane
+        >>> pane2 = window.split()
+        >>> window.previous_layout()
+        Window(...)
+        """
+        proc = self.cmd("previous-layout")
+
+        if proc.stderr:
+            raise exc.LibTmuxException(proc.stderr)
+
+        return self
+
     def link(
         self,
         target_session: str | Session,

tests/test_window.py

@@ -814,6 +814,45 @@ def test_select_layout_next_previous(session: Session) -> None:
     assert layout_after_prev == layout_before
 
 
+def test_next_layout(session: Session) -> None:
+    """Test Window.next_layout() cycles to the next layout."""
+    window = session.new_window(window_name="test_next_layout")
+    window.resize(height=40, width=80)
+    pane = window.active_pane
+    assert pane is not None
+    pane.split()
+
+    window.select_layout("even-horizontal")
+    window.refresh()
+    layout_before = window.window_layout
+
+    window.next_layout()
+    window.refresh()
+    layout_after = window.window_layout
+
+    assert layout_before != layout_after
+
+
+def test_previous_layout(session: Session) -> None:
+    """Test Window.previous_layout() cycles back."""
+    window = session.new_window(window_name="test_prev_layout")
+    window.resize(height=40, width=80)
+    pane = window.active_pane
+    assert pane is not None
+    pane.split()
+
+    window.select_layout("even-horizontal")
+    window.refresh()
+    layout_before = window.window_layout
+
+    window.next_layout()
+    window.previous_layout()
+    window.refresh()
+    layout_after = window.window_layout
+
+    assert layout_before == layout_after
+
+
 def test_select_layout_mutual_exclusion(session: Session) -> None:
     """Test that layout string and flags are mutually exclusive."""
     window = session.new_window(window_name="test_layout_mutex")