M3: doc comments for the structure commands and binding re-apply (#810)

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

crates/engine/src/cmd/structure.rs

@@ -10,6 +10,8 @@ use super::{CommandSpec, ok};
 use crate::params::*;
 use crate::{EngineError, Result, Session, bad, spec};
 
+/// The layer structure commands: group, frame, mask, boolean operations, flatten, auto layout
+/// add/remove, move to page and vector path edits.
 pub fn specs() -> Vec<CommandSpec> {
     vec![
         spec!("object.group", "Group selection", "{ids?, name?}", true, |s, p| wrap(s, p, Wrap::Group)),

crates/engine/src/cmd/styles.rs

@@ -1007,6 +1007,8 @@ pub(crate) fn apply_paint_bindings_on_load(doc: &mut Document) {
     doc.mark_dirty(pending);
 }
 
+/// Re-apply the variable bindings whose field passes `include`, on the `only` nodes (every bound
+/// node when `None`). Auto layout fields wait while their node has no auto layout.
 fn apply_bindings_matching(doc: &mut Document, only: Option<&std::collections::BTreeSet<NodeId>>, include: impl Fn(&str) -> bool) {
     use super::lists::{BoundList, list_binding};
     if doc.variables.variables.is_empty() {