feat(tauri): add single instance plugin and improve code formatting

This update introduces the tauri-plugin-single-instance to ensure that
only one instance of the application can run at a time. Additionally,
the code has been reformatted for better readability, with consistent
line breaks and spacing.

- Added single instance plugin to prevent multiple app instances
- Improved code formatting for better readability and maintenance
- Updated dependencies in Cargo.toml for new plugin integration

src-tauri/src/main.rs

@@ -19,7 +19,7 @@ use git::{
     restore_to_commit, search_code_introductions, stage_files, stash_apply, stash_drop, stash_pop,
     stash_push, undo_last_commit, unstage_files,
 };
-use tauri::Manager;
+use tauri::{Manager, AppHandle};
 
 #[tauri::command]
 fn close_splashscreen(app: tauri::AppHandle) -> Result<(), String> {
@@ -43,13 +43,21 @@ fn close_splashscreen(app: tauri::AppHandle) -> Result<(), String> {
 #[tokio::main]
 async fn main() {
     tauri::Builder::default()
+        .plugin(tauri_plugin_single_instance::init(|app, _, _| {
+            #[cfg(desktop)]
+            let _ = app.get_webview_window("main")
+                .expect("no main window")
+                .set_focus();
+        }))
         .plugin(tauri_plugin_updater::Builder::new().build())
-        .plugin(tauri_plugin_aptabase::Builder::new("A-SH-1344793789").with_options(
-                tauri_plugin_aptabase::InitOptions {
-                        host: Some("https://aptabase.cbsk-tech.de".to_string()),
-                        flush_interval:None
-                }
-        ).build())
+        .plugin(
+            tauri_plugin_aptabase::Builder::new("A-SH-1344793789")
+                .with_options(tauri_plugin_aptabase::InitOptions {
+                    host: Some("https://aptabase.cbsk-tech.de".to_string()),
+                    flush_interval: None,
+                })
+                .build(),
+        )
         .manage(SearchCancellationState::default())
         .manage(commit_ai::CommitAiEngine::new())
         .plugin(tauri_plugin_dialog::init())