Fix engine compile error: load export presets from presets JSON

Fixes #6911

Co-Authored-By: Claude Haiku 5.5 <noreply@anthropic.com>
Co-Authored-By: Claude Sonnet 5.5 <noreply@anthropic.com>
(cherry picked from commit bb7a5f2309)

crates/engine/src/presets/mod.rs

@@ -186,6 +186,7 @@ impl Session {
             tool_presets: take(&mut m, "tool_presets"),
             documents: take(&mut m, "documents"),
             recent_documents: take(&mut m, "recent_documents"),
+            export_presets: take(&mut m, "export_presets"),
             custom_shapes: take(&mut m, "custom_shapes"),
             layer_defaults: take(&mut m, "layer_defaults"),
             swatches: take(&mut m, "swatches"),

crates/engine/src/presets/tests.rs

@@ -774,3 +774,21 @@ fn a_damaged_preset_set_keeps_the_other_sets() {
     assert_eq!(next.presets.gradients.len(), Session::new().presets.gradients.len());
     assert_eq!(next.presets.documents, s.presets.documents);
 }
+
+// ------------------------------------------------------------------ export presets
+
+#[test]
+fn export_presets_survive_a_presets_json_round_trip() {
+    let mut s = Session::new();
+    s.execute("file.export.presets.save", json!({"name": "Web", "settings": {"format": "jpg", "quality": 70}})).unwrap();
+    assert_eq!(s.presets.export_presets.len(), 1);
+
+    let saved = s.presets.to_json(&s);
+    assert_eq!(saved["export_presets"].as_array().map(Vec::len), Some(1));
+
+    let mut restored = Session::new();
+    restored.load_presets_json(saved);
+    assert_eq!(restored.presets.export_presets.len(), 1);
+    assert_eq!(restored.presets.export_presets[0].name, "Web");
+    assert_eq!(restored.presets.export_presets[0].settings.format, "jpg");
+}