feat: add close confirmation modal with minimize to tray option

Implemented a confirmation modal when users try to close the application:
- Modal always shows with three options: Cancel, Minimize to Tray, Close Application
- Detects if Claude is actively running and shows appropriate warning message
- Removed minimize_to_tray config setting (no longer needed)
- Added core:window:allow-hide permission for window hiding
- Created CloseAppConfirmModal component with keyboard shortcuts (Escape to cancel)
- Added close_application command to properly exit the app
- Backend emits window-close-requested event for frontend to handle

This provides better UX by giving users clear choices every time they close,
preventing accidental closures during active work sessions.

src-tauri/src/commands.rs

@@ -1154,6 +1154,19 @@ pub async fn log_discord_rpc(
     Ok(())
 }
 
+#[tauri::command]
+pub async fn close_application(app_handle: AppHandle) -> Result<(), String> {
+    // Get the main window
+    if let Some(window) = app_handle.get_webview_window("main") {
+        // Hide the window first for a smoother close
+        let _ = window.hide();
+    }
+
+    // Exit the application
+    app_handle.exit(0);
+    Ok(())
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;