feat(kon): wire Tauri shell — thin commands, ProviderRegistry, tray

- lib.rs rewritten from scaffold to full app setup (~70 lines)
- AppState holds Arc<LocalEngine> for Whisper and Parakeet
- commands/models.rs: download, check, list, load for both engines
  Maps legacy size strings (Tiny/Base/Small/Medium) to ModelId
- commands/transcription.rs: transcribe_pcm, transcribe_file, transcribe_pcm_parakeet
  Delegates to LocalEngine.transcribe_sync() + post_process_segments()
- commands/audio.rs: save_audio via kon_audio::write_wav
- commands/windows.rs: open_task_window, open_viewer_window
- commands/llm.rs: 8 stub commands preserved for frontend compatibility
- tray.rs: extracted system tray setup (show, status, quit, click-to-show)
- Close-to-tray behaviour preserved
- All 25 v0.2 command names preserved for Svelte frontend compatibility
- clippy clean

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

src-tauri/src/lib.rs

@@ -1,9 +1,83 @@
+mod commands;
+mod tray;
+
+use std::sync::Arc;
+
+use tauri::Manager;
+
+use kon_core::types::EngineName;
+use kon_transcription::LocalEngine;
+
+/// Shared app state holding the transcription engines.
+pub struct AppState {
+    pub whisper_engine: Arc<LocalEngine>,
+    pub parakeet_engine: Arc<LocalEngine>,
+}
+
 #[cfg_attr(mobile, tauri::mobile_entry_point)]
 pub fn run() {
     tauri::Builder::default()
         .plugin(tauri_plugin_opener::init())
         .plugin(tauri_plugin_dialog::init())
         .plugin(tauri_plugin_global_shortcut::Builder::new().build())
+        .manage(AppState {
+            whisper_engine: Arc::new(LocalEngine::new(
+                EngineName::new("whisper"),
+            )),
+            parakeet_engine: Arc::new(LocalEngine::new(
+                EngineName::new("parakeet"),
+            )),
+        })
+        .setup(|app| {
+            if let Err(e) = tray::setup(app) {
+                eprintln!("Failed to setup tray: {e}");
+            }
+
+            // Close-to-tray: hide window instead of exiting
+            let main_window = app.get_webview_window("main").unwrap();
+            let win = main_window.clone();
+            main_window.on_window_event(move |event| {
+                if let tauri::WindowEvent::CloseRequested { api, .. } = event
+                {
+                    api.prevent_close();
+                    let _ = win.hide();
+                }
+            });
+
+            Ok(())
+        })
+        .invoke_handler(tauri::generate_handler![
+            // Whisper model management
+            commands::models::download_model,
+            commands::models::check_model,
+            commands::models::list_models,
+            commands::models::load_model,
+            commands::models::check_engine,
+            // Parakeet model management
+            commands::models::download_parakeet_model,
+            commands::models::check_parakeet_model,
+            commands::models::list_parakeet_models,
+            commands::models::load_parakeet_model,
+            commands::models::check_parakeet_engine,
+            // Transcription
+            commands::transcription::transcribe_pcm,
+            commands::transcription::transcribe_file,
+            commands::transcription::transcribe_pcm_parakeet,
+            // Audio
+            commands::audio::save_audio,
+            // Windows
+            commands::windows::open_task_window,
+            commands::windows::open_viewer_window,
+            // LLM stubs
+            commands::llm::download_llm_model,
+            commands::llm::check_llm_model,
+            commands::llm::list_llm_models,
+            commands::llm::load_llm_model,
+            commands::llm::check_llm_engine,
+            commands::llm::llm_generate,
+            commands::llm::llm_extract_tasks,
+            commands::llm::llm_format_transcript,
+        ])
         .run(tauri::generate_context!())
         .expect("error while running Kon");
 }