Keep paragraph styles aligned in Find and Replace with line breaks

Found while testing crates/engine/src/cmd/typemenu.rs:668 (find_replace / edit_runs)

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

crates/engine/src/cmd/typemenu.rs

@@ -665,16 +665,39 @@ fn find_replace(s: &mut Session, p: &Value) -> Result<Value> {
     if total == 0 {
         return Ok(json!({ "count": 0 }));
     }
-    edit_runs::<()>(s, "Replace", &ids, |text, _| {
-        let mut out = String::with_capacity(text.len());
-        let mut last = 0;
-        for (a, b) in find_all(text, &find, mc, ww) {
-            out.push_str(&text[last..a]);
-            out.push_str(&rep);
-            last = b;
+    super::overprint::edit_counted(s, "Replace", |d| {
+        let mut changed = 0;
+        for id in &ids {
+            let Some(NodeKind::Text(t)) = d.node_mut(*id).map(|n| &mut n.kind) else { continue };
+            // Matches as (run, start, end) with offsets inside the run. Inline graphics are art, not
+            // characters to rewrite.
+            let mut hits = vec![];
+            let mut base = 0;
+            for (ri, r) in t.runs.iter().enumerate() {
+                if r.inline.is_none() {
+                    for (a, b) in find_all(&r.text, &find, mc, ww) {
+                        if r.text.get(a..b) != Some(rep.as_str()) {
+                            hits.push((ri, base + a, base + b, a, b));
+                        }
+                    }
+                }
+                base += r.text.len();
+            }
+            if hits.is_empty() {
+                continue;
+            }
+            // Last match first, so the offsets of earlier ones stay valid. The paragraph styles follow
+            // each edit, as `text.editRange` does.
+            for (ri, ta, tb, a, b) in hits.into_iter().rev() {
+                t.splice_paras(ta, tb, &rep);
+                if let Some(r) = t.runs.get_mut(ri) {
+                    r.text.replace_range(a..b, &rep);
+                }
+            }
+            changed += 1;
+            refresh_bounds(t);
         }
-        out.push_str(&text[last..]);
-        out
+        Ok(changed)
     })?;
     Ok(json!({ "count": total }))
 }