[Request] Show cached apps

### Guidelines

- [x] I have searched the issue tracker for [open](https://github.com/Droid-ify/client/issues) and [closed](https://github.com/Droid-ify/client/issues?q=is%3Aissue+is%3Aclosed) issues that are similar to the feature request I want to file, without success.
- [x] I'm not requesting app support for a specific repo — that's up to repo maintainers
- [x] I understand this might not get built (Droid-ify is maintained by a single person)

### Problem

If you install multiple apps at once, Droid-ify malfunctions in such a way that when you tap on a notification stating that an app has been downloaded and is ready for installation, the system pop-up with the “Install” button doesn’t appear. In other words, the problem is specifically that this popup stops appearing, and as a result, it’s impossible to install the downloaded apps.

You have to force-close Droid-ify and manually search for all these apps again to try installing them. But this time, when you try to install them, Droid-ify crashes instantly when you tap the “Install” button. And this happens for every previously downloaded app in the cache.

So it would be nice to have a tab or page with a list of apps that have already been downloaded and are in the cache, ready for installation.

Translated with DeepL.com (free version)

### Proposed solution

a list of apps that have already been downloaded and are in the cache, ready for installation.

### Extras

And fix crashes.

Start by reproducing the multi-app download flow, then tap a completion notification and try installing an app previously downloaded to the cache. Done means cached apps are listed in a dedicated tab or page, can be installed from there, and the reported crash no longer occurs.

Written by the indexing model from the issue text.