added the new multiple levels to the save/load

src/main.rs

@@ -141,19 +141,21 @@ impl eframe::App for DungeonApp {
             self.push_undo_snapshot();
             self.regenerate_layout();
         } else if panel_result.save_clicked {
-            if self.settings.active_level_index < self.levels.len() {
-                let layout = &self.levels[self.settings.active_level_index];
-                let svg = exporter::build_svg(layout, &self.settings);
-                if let Err(err) = saveandload::save_dungeon(&self.settings, layout, svg) {
-                    eprintln!("{err}");
-                }
+            let mut layouts = Vec::new();
+            let mut svgs = Vec::new();
+            for layout in &self.levels {
+                layouts.push(layout.clone());
+                svgs.push(exporter::build_svg(layout, &self.settings));
+            }
+            if let Err(err) = saveandload::save_dungeon(&self.settings, layouts, svgs) {
+                eprintln!("{err}");
             }
         } else if panel_result.load_clicked {
             match saveandload::load_dungeon() {
                 Ok(data) => {
                     self.push_undo_snapshot();
                     self.settings = data.settings;
-                    self.levels = vec![data.layout];
+                    self.levels = data.layouts;
                     self.settings.active_level_index = 0;
                     // Don't regenerate_layout() here to preserve the exact loaded state.
                 }

src/saveandload.rs

@@ -9,14 +9,14 @@ use crate::ui::UiSettings;
 #[derive(Serialize, Deserialize)]
 pub struct DungeonSave {
     pub settings: UiSettings,
-    pub layout: DungeonLayout,
-    pub svg: String,
+    pub layouts: Vec<DungeonLayout>,
+    pub svgs: Vec<String>,
 }
 
 pub fn save_dungeon(
     settings: &UiSettings,
-    layout: &DungeonLayout,
-    svg: String,
+    layouts: Vec<DungeonLayout>,
+    svgs: Vec<String>,
 ) -> Result<PathBuf, String> {
     let path = FileDialog::new()
         .set_title("Save Dungeon State")
@@ -27,8 +27,8 @@ pub fn save_dungeon(
 
     let save_data = DungeonSave {
         settings: settings.clone(),
-        layout: layout.clone(),
-        svg,
+        layouts,
+        svgs,
     };
 
     let json = serde_json::to_string_pretty(&save_data)