Add launcher preferences and modular landing studio [skip ci]

launcher/src-tauri/src/accounts.rs

@@ -135,7 +135,7 @@ fn save_panel_account(state: &AppState, panel: &str, auth: AuthResponse) -> Resu
 }
 
 pub async fn rename_panel(state: &AppState, username: &str, password: &str) -> Result<Account> {
-    if state.game.lock().unwrap().is_some() || state.task.lock().unwrap().as_ref().is_some_and(|t| !t.is_finished()) {
+    if !state.game.lock().unwrap().is_empty() || state.task.lock().unwrap().as_ref().is_some_and(|t| !t.is_finished()) {
         bail!("close Minecraft and wait for any installation to finish before changing your username");
     }
     let panel = state.panel_url().ok_or_else(|| anyhow!("no panel configured"))?;