Align, Reflect and Shear: object.align needs a direction; unknown choices are errors

object.align with neither horizontal nor vertical returned success
and moved nothing. The command palette, and a key bound to it in
Keyboard Shortcuts, run it with no params. It now returns
"give horizontal or vertical", as object.distribute already did.
An action recorded while Align ran from the palette or a bound key
contains an object.align step with no params. Playing that action now
fails at that step, and command.batch rolls back the whole action.

Values outside a parameter's choices were read as another choice or
ignored. Align ignored an unknown horizontal or vertical and aligned
to the selection for an unknown to value. Distribute read an unknown
direction as center. Distribute Spacing and Shear read any axis other
than "vertical" as horizontal, and Reflect read any axis other than
"horizontal" or a number as vertical. A bounds or to value that was
not a string fell back to the default, and a spacing that was not a
number gave automatic spacing. The commands now return an error that
names such a value, before they move anything or record an undo
step. When a to, bounds, axis or spacing value is missing or null,
the command uses the parameter's default: Distribute Spacing without
an axis spaces the objects horizontally.

The run_command description and docs/mcp.md showed object.align with
an align param it does not have; they now use horizontal. The new
status-bar messages have rows in the de, es, fr, it, ja, ru and uk
catalogs.

Docs: docs/mcp.md, docs/target-app-parity.md.

crates/engine/src/tests.rs

@@ -381,6 +381,64 @@ fn clipping_and_compound() {
     assert_eq!(s.doc().unwrap().selection.objects, vec![b]);
 }
 
+/// `object.align` without `horizontal` or `vertical` (an unknown key such as `align` counts as
+/// neither) returns an error: nothing moves, and the undo and redo stacks stay as they were.
+#[test]
+fn align_without_a_direction_is_refused() {
+    let mut s = session();
+    let a = rect(&mut s, 0.0, 0.0, 10.0, 10.0);
+    let b = rect(&mut s, 50.0, 30.0, 10.0, 10.0);
+    s.execute("select.set", &json!({"ids": [a.0, b.0]})).unwrap();
+    s.execute("object.move", &json!({"dx": 5, "dy": 0})).unwrap();
+    s.execute("edit.undo", &json!({})).unwrap();
+    let stacks = |s: &Session| (s.doc().unwrap().history.undo.len(), s.doc().unwrap().history.redo.len());
+    let before = stacks(&s);
+    for p in [json!({}), json!({"align": "left"}), json!({"to": "artboard"}), json!({"horizontal": null, "vertical": null})] {
+        let e = s.execute("object.align", &p).expect_err(&p.to_string());
+        assert_eq!(e.to_string(), "invalid parameters for `object.align`: give horizontal or vertical", "{p}");
+    }
+    assert_eq!(stacks(&s), before, "no undo step, and the redo step is kept");
+    assert_eq!(s.doc().unwrap().doc.node(b).unwrap().geometric_bounds().unwrap().x0, 50.0, "nothing moved");
+}
+
+/// Align, Distribute and Distribute Spacing return an error that names a value outside their
+/// choices: nothing moves and no undo step is recorded. A null value counts as not given, and
+/// Distribute Spacing without an `axis` spaces the objects horizontally.
+#[test]
+fn align_and_distribute_reject_bad_params_without_changing_state() {
+    let mut s = session();
+    let ids: Vec<NodeId> = [0.0, 50.0, 200.0].into_iter().map(|x| rect(&mut s, x, x / 2.0, 10.0, 10.0)).collect();
+    s.execute("select.set", &json!({"ids": ids.iter().map(|id| id.0).collect::<Vec<_>>()})).unwrap();
+    let bounds = |s: &Session| ids.iter().map(|id| s.doc().unwrap().doc.node(*id).unwrap().geometric_bounds().unwrap()).collect::<Vec<_>>();
+    let before = bounds(&s);
+    let undo = s.doc().unwrap().history.undo.len();
+    let h = "horizontal must be \"left\", \"center\" or \"right\"";
+    let v = "vertical must be \"top\", \"center\" or \"bottom\"";
+    for (cmd, p, msg) in [
+        ("object.align", json!({"horizontal": "middle"}), format!("{h}, not `middle`")),
+        ("object.align", json!({"vertical": "centre"}), format!("{v}, not `centre`")),
+        ("object.align", json!({"horizontal": true}), format!("{h}, not `true`")),
+        ("object.align", json!({"horizontal": "left", "to": "page"}), "to must be \"selection\", \"artboard\" or \"key\", not `page`".into()),
+        ("object.align", json!({"horizontal": "left", "to": 0}), "to must be \"selection\", \"artboard\" or \"key\", not `0`".into()),
+        ("object.align", json!({"horizontal": "left", "bounds": false}), "bounds must be \"preview\" or \"geometric\", not `false`".into()),
+        ("object.align", json!({"horizontal": "left", "vertical": "middle"}), format!("{v}, not `middle`")),
+        ("object.distribute", json!({"horizontal": "middle"}), format!("{h}, not `middle`")),
+        ("object.distribute", json!({"vertical": "centre"}), format!("{v}, not `centre`")),
+        ("object.distribute", json!({"horizontal": "left", "vertical": "middle"}), format!("{v}, not `middle`")),
+        ("object.distributeSpacing", json!({"axis": "diagonal"}), "axis must be \"horizontal\" or \"vertical\", not `diagonal`".into()),
+        ("object.distributeSpacing", json!({"axis": "vertical", "spacing": "5"}), "spacing must be a number, not `\"5\"`".into()),
+    ] {
+        let e = s.execute(cmd, &p).expect_err(&format!("{cmd} {p}"));
+        assert_eq!(e.to_string(), format!("invalid parameters for `{cmd}`: {msg}"));
+    }
+    assert_eq!(bounds(&s), before, "nothing moved");
+    assert_eq!(s.doc().unwrap().history.undo.len(), undo, "no undo step");
+    s.execute("object.align", &json!({"horizontal": null, "vertical": "top", "to": null, "bounds": null})).unwrap();
+    assert!(bounds(&s).iter().all(|b| b.y0 == 0.0), "aligned to the top");
+    s.execute("object.distributeSpacing", &json!({"axis": null, "spacing": null})).unwrap();
+    assert_eq!(bounds(&s).iter().map(|b| b.x0).collect::<Vec<_>>(), [0.0, 100.0, 200.0], "equal horizontal gaps");
+}
+
 #[test]
 fn align_left() {
     let mut s = session();