Resolve and test style changes through Arc::make_mut after the shared-stylesheet change on main

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

crates/docx/tests/it/roundtrip.rs

@@ -309,7 +309,7 @@ fn styles_and_lists_round_trip() {
 fn tracked_style_definition_change_round_trips() {
     let mut d = Document::new();
     d.revisions.push(Revision { kind: RevisionKind::Format, author: "Ana".into(), date: "2026-10-17T10:00:00Z".into(), move_name: None });
-    d.styles.upsert(Style {
+    std::sync::Arc::make_mut(&mut d.styles).upsert(Style {
         id: "Mine".into(),
         name: "Mine".into(),
         kind: StyleKind::Paragraph,

crates/engine/src/cmd/fmt_revisions.rs

@@ -242,7 +242,7 @@ pub(crate) fn record(s: &mut Session, id: &str, before: &Document) {
             r.blocks(&pb.blocks, &mut pa.blocks, 0);
         }
     }
-    r.styles(&before.styles.styles, &mut doc.styles.styles);
+    r.styles(&before.styles.styles, &mut std::sync::Arc::make_mut(&mut doc.styles).styles);
 }
 
 /// Record the paragraph formatting a command changed on the paragraph at `path` whose text it also

crates/engine/src/cmd/review/changes.rs

@@ -101,7 +101,7 @@ fn resolve_styles_sel(s: &mut Session, selected: bool, accept: bool) -> Result<b
     if !s.doc.styles.styles.iter().any(|st| st.para_change.is_some() || st.chr_change.is_some()) {
         return Ok(false);
     }
-    for st in &mut s.doc.styles.styles {
+    for st in &mut std::sync::Arc::make_mut(&mut s.doc.styles).styles {
         fmt_revisions::resolve_style(st, accept);
     }
     Ok(true)
@@ -209,8 +209,10 @@ fn resolve_all(s: &mut Session, accept: bool) -> CmdResult {
         fmt_revisions::resolve_containers(&mut part.blocks, accept, 0);
     }
     fmt_revisions::resolve_section(&mut s.doc.last_section, accept);
-    for st in &mut s.doc.styles.styles {
-        fmt_revisions::resolve_style(st, accept);
+    if s.doc.styles.styles.iter().any(|st| st.para_change.is_some() || st.chr_change.is_some()) {
+        for st in &mut std::sync::Arc::make_mut(&mut s.doc.styles).styles {
+            fmt_revisions::resolve_style(st, accept);
+        }
     }
     // The note separators are block lists of their own, not stories; they must not keep ids of
     // revisions that are about to be dropped.

crates/engine/src/tests.rs

@@ -3319,7 +3319,7 @@ fn non_property_style_changes_are_not_recorded_as_formatting() {
     let mut s = s();
     run(&mut s, "review.trackChanges", json!({"value": true}));
     let before = s.doc.clone();
-    let st = s.doc.styles.get_mut("Heading1").unwrap();
+    let st = std::sync::Arc::make_mut(&mut s.doc.styles).get_mut("Heading1").unwrap();
     st.based_on = Some("Title".into());
     st.next = Some("Heading2".into());
     st.linked = Some("Emphasis".into());
@@ -3363,7 +3363,7 @@ fn tracked_style_change_round_trips_through_docx() {
 fn rejecting_a_reopened_style_change_keeps_style_metadata() {
     use wordcraft_doc::styles::{Style, StyleKind, TableStyleParts};
     let mut s = s();
-    s.doc.styles.upsert(Style {
+    std::sync::Arc::make_mut(&mut s.doc.styles).upsert(Style {
         id: "GridX".into(),
         name: "Grid X".into(),
         kind: StyleKind::Table,