[HH9] picture.reset: document and pin what it keeps (frame shape, size, position)

PowerPoint: Reset Picture discards the picture's formatting changes
(corrections, recolor, artistic effect, picture-style effects and outline);
Reset Picture & Size also restores the size. The frame shape set by Change
Shape is not touched. Ours already left the geometry alone (the reported
geometry wipe does not reproduce); effects, outline and crop are picture
formatting that PowerPoint discards too, so they stay reset (declined:
parity). Added the regression test and the command doc.

Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>

crates/engine/src/cmd/shape.rs

@@ -165,7 +165,15 @@ pub fn specs() -> Vec<CommandSpec> {
             has_selection,
             picture_adjust
         ),
-        cmd!("picture.reset", "Reset Picture", ["Picture Format", "Adjust"], None, "{ids?}", has_selection, picture_reset),
+        cmd!(
+            "picture.reset",
+            "Reset Picture",
+            ["Picture Format", "Adjust"],
+            None,
+            "{ids?} (discards the picture's formatting: adjustments, artistic effect, crop, transparency, picture-style effects and outline; the frame shape from Change Shape or Crop to Shape, the size and the position stay)",
+            has_selection,
+            picture_reset
+        ),
         cmd!(
             "picture.change",
             "Change Picture",

crates/engine/src/tests.rs

@@ -5646,3 +5646,29 @@ fn invalid_ids_array_never_falls_back_to_the_selection() {
         assert!(s.doc().unwrap().shape(deckcraft_model::ShapeId(a as u32)).is_some(), "shape deleted for {ids}");
     }
 }
+
+/// HH9: Reset Picture discards the picture's formatting (adjustments, artistic effect, picture
+/// style effects and outline) but not the frame's shape (Change Shape / Crop to Shape).
+#[test]
+fn picture_reset_keeps_the_frame_shape() {
+    let mut img = image::RgbaImage::new(40, 30);
+    img.pixels_mut().for_each(|p| *p = image::Rgba([200, 30, 30, 255]));
+    let mut png = Vec::new();
+    image::DynamicImage::ImageRgba8(img).write_to(&mut std::io::Cursor::new(&mut png), image::ImageFormat::Png).unwrap();
+    let mut s = Session::with_new();
+    s.execute("slide.new", &json!({"layout": "blank"})).unwrap();
+    s.execute("insert.picture", &json!({"name": "a.png", "data": cmd::base64_encode(&png)})).unwrap();
+    s.execute("shape.change", &json!({"preset": "roundRect"})).unwrap();
+    s.execute("picture.adjust", &json!({"brightness": 0.3})).unwrap();
+    let geom = s.doc().unwrap().selected_shapes()[0].geom.clone();
+    assert_ne!(geom, deckcraft_model::Geom::preset("rect"));
+    s.execute("picture.reset", &json!({})).unwrap();
+    let sh = s.doc().unwrap().selected_shapes()[0].clone();
+    assert_eq!(sh.geom, geom, "the frame shape stays");
+    match &sh.kind {
+        deckcraft_model::ShapeKind::Picture { fill } => assert_eq!(fill.adjust, Default::default()),
+        _ => panic!("not a picture"),
+    }
+    let doc = command_specs().iter().find(|c| c.id == "picture.reset").unwrap().params;
+    assert!(doc.contains("frame shape"), "{doc}");
+}