feat: Guide users to install PWA

[Misofist]

This builds on the work done by Pecacheu in #1024, but completely reworks the UX.

NOTE: A lot of the screenshots below look ugly, that's because this is designed to work alongside #835. It looks good when that PR is also included, I just didn't want to misrepresent what's included within this PR in my screenshots.

No modal window is shown. Instead, a new "Install" option has been added to the Settings menu.

On browsers that support the beforeinstallprompt event, this page contains a button to install the PWA.

Clicking this button starts the PWA install experience:

This also gracefully handles the case where the user declines the installation:

For browsers which do not support the beforeinstallprompt event, manual installation instructions are shown:

The install button is hidden within the PWA itself:

The install button also only appears on mobile browsers, since currently on desktop I think there is little point in installing the PWA.

I also updated the way we use Vite PWA to follow their best practices for SW updates: https://vite-pwa-org.netlify.app/guide/periodic-sw-updates.html#handling-edge-cases

[DeclanChidlow]

For the 'refresh to try again', a refresh button could be made present on the page for ease of use.

Also, I wrote a full article on detecting and styling based on if the app is installed as a PWA which could well be of use: https://www.smashingmagazine.com/2025/08/optimizing-pwas-different-display-modes/

[Misofist]

For the 'refresh to try again', a refresh button could be made present on the page for ease of use.

Good idea! I'll add that in when I'm at my computer.

Also, I wrote a full article on detecting and styling based on if the app is installed as a PWA which could well be of use: https://www.smashingmagazine.com/2025/08/optimizing-pwas-different-display-modes/

Great article. I don't think this changes anything, since Stoat's formatting is handled via JS and not via stylesheets. This is also intended to pair with #835 or similar, so I expect that the PWA manifest will only specify standalone mode.

But let me know if I've missed anything. :)

[DeclanChidlow]

Ah, GitHub had a fart and didn't show me the full file, only the setting for iOS bit so I thought it'd been missed. Disregard.

[Pecacheu]

This does seem like a better way of doing it yea, I'll test it out soon