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/index.css

@@ -5,9 +5,9 @@
 }
 
 body {
-  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Roboto', 'Oxygen',
-    'Ubuntu', 'Cantarell', 'Fira Sans', 'Droid Sans', 'Helvetica Neue',
-    sans-serif;
+  font-family:
+    -apple-system, BlinkMacSystemFont, "Segoe UI", "Roboto", "Oxygen", "Ubuntu",
+    "Cantarell", "Fira Sans", "Droid Sans", "Helvetica Neue", sans-serif;
   -webkit-font-smoothing: antialiased;
   -moz-osx-font-smoothing: grayscale;
   background-color: #f5f5f5;