G1: Alt-drag an existing ruler guide to swap its orientation

Match the public shortcut reference: Alt while dragging converts horizontal and vertical, with snapping on the new axis; guide.move accepts vertical on the index form.

Co-authored-by: Cursor <cursoragent@cursor.com>

crates/engine/src/cmd/docmenu.rs

@@ -207,7 +207,7 @@ pub fn specs() -> Vec<CommandSpec> {
             "Move Guide",
             [],
             None,
-            "{index, pos: pt} | {dx?, dy?: pt, copy?: bool} put ruler guide `index` at `pos`, or move the selected guides (vertical ones by dx, horizontal ones by dy); copy leaves them and selects the moved copies",
+            "{index, pos: pt, vertical?: bool} | {dx?, dy?: pt, copy?: bool} put ruler guide `index` at `pos` (and swap its orientation when `vertical` is given), or move the selected guides (vertical ones by dx, horizontal ones by dy); copy leaves them and selects the moved copies",
             guides_unlocked,
             guide_move
         ),
@@ -769,6 +769,9 @@ pub(crate) fn guide_move(s: &mut Session, p: &Value) -> Result<Value> {
         s.edit("Move Guide", |d, _| {
             if let Some(g) = d.guides.get_mut(i) {
                 g.pos = pos;
+                if p.get("vertical").is_some() {
+                    g.vertical = bool_or(p, "vertical", false);
+                }
             }
             Ok(())
         })?;

crates/engine/src/tests_menucmds.rs

@@ -2011,6 +2011,14 @@ fn ruler_guides_and_lock() {
     assert!(s.execute("guide.remove", &json!({"index": 0})).is_err());
 }
 
+#[test]
+fn guide_move_can_swap_orientation() {
+    let mut s = session();
+    s.execute("guide.add", &json!({"vertical": false, "pos": 50})).unwrap();
+    s.execute("guide.move", &json!({"index": 0, "pos": 120, "vertical": true})).unwrap();
+    assert_eq!((s.doc().unwrap().doc.guides[0].vertical, s.doc().unwrap().doc.guides[0].pos), (true, 120.0));
+}
+
 /// #1534: Lock Guides locks the paths made into guides too: they can't be selected (so neither
 /// moved, reshaped nor deleted), by a click, a marquee or Select All, and locking lets them go.
 #[test]