Add Tauri launcher with Svelte UI

- Accounts: panel login/sign-up, Microsoft device-code sign-in, offline
  play; tokens encrypted with a key kept in the OS credential store
- Home: instance rail, live server status, news feed, social links,
  Play button with download progress, speed and ETA
- Full settings: accounts, memory/resolution/after-launch behaviour,
  Java and GC presets, Minecraft keybind editor applied to options.txt,
  theme overrides, storage manager, self-update via GitHub releases
- Game console, crash dialog with hints, per-instance overrides
- Live admin branding (colours, fonts, backgrounds, custom CSS)
- Online install tests for vanilla/Fabric/Quilt/Forge/NeoForge (CI)

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_011ARcGWxLx21FwXJ3yfGriS

launcher/src-tauri/src/lib.rs

@@ -0,0 +1,78 @@
+//! ScopeNet launcher (Tauri shell). The heavy lifting lives in
+//! `scopenet-core`; this crate wires it to the UI.
+
+mod accounts;
+mod commands;
+mod game;
+mod secrets;
+mod settings;
+mod state;
+mod updater;
+
+use tauri::Manager;
+
+pub fn run() {
+    tracing_subscriber::fmt()
+        .with_env_filter(tracing_subscriber::EnvFilter::try_from_default_env().unwrap_or_else(|_| "info".into()))
+        .init();
+
+    tauri::Builder::default()
+        // A second launch just focuses the existing window.
+        .plugin(tauri_plugin_single_instance::init(|app, _args, _cwd| {
+            if let Some(w) = app.get_webview_window("main") {
+                w.show().ok();
+                w.unminimize().ok();
+                w.set_focus().ok();
+            }
+        }))
+        .plugin(tauri_plugin_dialog::init())
+        .plugin(tauri_plugin_opener::init())
+        .setup(|app| {
+            let data_dir = app.path().app_data_dir()?;
+            app.manage(state::AppState::new(data_dir));
+            // The window starts hidden and the UI reveals it once painted (no
+            // white flash). If the UI never does, show it anyway.
+            let handle = app.handle().clone();
+            std::thread::spawn(move || {
+                std::thread::sleep(std::time::Duration::from_secs(4));
+                if let Some(w) = handle.get_webview_window("main") {
+                    if !w.is_visible().unwrap_or(true) {
+                        tracing::warn!("UI didn't signal ready; showing window");
+                        w.show().ok();
+                    }
+                }
+            });
+            Ok(())
+        })
+        .invoke_handler(tauri::generate_handler![
+            commands::bootstrap,
+            commands::refresh_manifest,
+            commands::set_panel_url,
+            commands::save_settings,
+            commands::login_panel,
+            commands::register_panel,
+            commands::add_offline,
+            commands::ms_start,
+            commands::ms_finish,
+            commands::ms_cancel,
+            commands::select_account,
+            commands::remove_account,
+            commands::launch,
+            commands::repair_instance,
+            commands::cancel_launch,
+            commands::kill_game,
+            commands::instance_local,
+            commands::ping_server,
+            commands::open_folder,
+            commands::open_file,
+            commands::storage_info,
+            commands::delete_instance_data,
+            commands::clear_cache,
+            commands::detect_java,
+            commands::check_update,
+            commands::install_update,
+            commands::show_window,
+        ])
+        .run(tauri::generate_context!())
+        .expect("error while running the launcher");
+}