Commands: ids leave out an object listed with a group that holds it, as the selection does

Commands that read the selection through edit::selected_roots leave
out an object whose group is also selected (edit::roots_of). Fourteen
places that read `ids` kept an object listed together with its group.
Given ids that list an object and a group that holds it, Make Repeat
failed with "no such object", New Symbol failed or stored the object
twice in the symbol, and object.transform moved it twice (20 pt for a
10 pt move).

These places now pass explicit ids through edit::outermost, which
drops an id whose ancestor is also listed, with the filter that
roots_of runs on the selection (now edit::without_inner). Nothing else
is dropped or replaced: unlike roots_of, it keeps layers and
compound-path members. A list without nesting gives the same result as
before. Commands that take both ids and the selection as listed, such
as paint.setFill without item, are unchanged.

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

crates/engine/src/cmd/gradient.rs

@@ -8,7 +8,7 @@ use vectorcraft_geom::{Affine, Point, Rect};
 use vectorcraft_tools::params::color_json;
 
 use super::appearance::{ItemTarget, edit_items, edits_stroke, item_target};
-use super::edit::selected_roots;
+use super::edit::{outermost, selected_roots};
 use super::paint::swatch_solid;
 use super::*;
 use crate::EngineError;
@@ -512,7 +512,7 @@ fn set_gradient_geom(s: &mut Session, p: &Value) -> Result<Value> {
     let stroke = edits_stroke(s, p, item, !s.fill_active)?;
     let item = item.of_kind(s, !stroke);
     let targets = match item {
-        ItemTarget::Top => leaf_targets(s, &ids_param(p, "ids").map_or_else(|| selected_roots(s), Ok)?)?,
+        ItemTarget::Top => leaf_targets(s, &ids_param(p, "ids").map_or_else(|| selected_roots(s), |ids| Ok(outermost(&s.doc()?.doc, ids)))?)?,
         _ => item.targets(s, p)?,
     };
     if targets.is_empty() {