Check if all used packages are installed

E.g. it tries to `unzip` blindly and so forth.

- [ ] `unzip`
- [ ] `whiskermenu`:
   <img width="1280" height="800" alt="Image" src="https://github.com/user-attachments/assets/4ceb8988-c555-4a59-b656-d38f30df20ef" />
- [ ] `power-manager-plugin`:
   <img width="1280" height="800" alt="Image" src="https://github.com/user-attachments/assets/55f5c269-6d2f-4827-9b77-2a03d412d436" />