feat: v0.2.0 - add system tray, clean up unused role field

- Replace text '+' icon with centered SVG plus icon for the add-provider button
- Add system tray: minimize-to-tray and quit-from-tray menu (minimize hides window, close exits app)
- Remove unused model role field (no functional effect, only stored/displayed)
- Fix multiple providers showing as active in Kimi Code mode: only the default_model's provider is marked active
- Copy /reload to clipboard after provider switch as a convenience hint
- Bump version to 0.2.0

src-tauri/tauri.conf.json

@@ -1,7 +1,7 @@
 {
-  "productName": "Pi Switch",
-  "version": "0.1.0",
-  "identifier": "com.piswitch.app",
+  "productName": "Kimi Switch",
+  "version": "0.2.0",
+  "identifier": "com.kimiswitch.app",
   "build": {
     "beforeDevCommand": "npm run dev",
     "beforeBuildCommand": "npm run build",
@@ -11,7 +11,7 @@
   "app": {
     "windows": [
       {
-        "title": "Pi Switch",
+        "title": "Kimi Switch",
         "width": 1200,
         "height": 800,
         "minWidth": 1000,