feat: Open main window on tray icon click (Windows)

Implemented functionality to open the main application window when the system tray icon is left-clicked on Windows.

This is achieved by adding a handler for `SystemTrayEvent::LeftClick` in `src-tauri/src/main.rs`.
The handler ensures the main window is shown and brought into focus. This change is specific to the Windows platform.

src-tauri/src/main.rs

@@ -945,6 +945,12 @@ async fn main() {
           }
         }
       },
+      #[cfg(target_os = "windows")]
+      SystemTrayEvent::LeftClick { .. } => {
+        let window = app.get_window("main").unwrap();
+        window.show().unwrap();
+        window.set_focus().unwrap();
+      }
       _ => {}
     })
     .on_window_event(|event| {