chore: format code and fix bundle identifier for v3.0.0 release

- Format all TypeScript/React code with Prettier
- Format all Rust code with cargo fmt
- Fix bundle identifier from .app to .desktop to avoid macOS conflicts
- Prepare codebase for v3.0.0 Tauri release

src-tauri/tauri.conf.json

@@ -2,7 +2,7 @@
   "$schema": "https://schema.tauri.app/config/2",
   "productName": "CC Switch",
   "version": "3.0.0",
-  "identifier": "com.ccswitch.app",
+  "identifier": "com.ccswitch.desktop",
   "build": {
     "frontendDist": "../dist",
     "devUrl": "http://localhost:3000",