fix: Update start_url to root

[mattdsteele]

👋

I'd love to use Flux as a PWA (on Windows 11), but I'm finding after installing the Vercel-hosted webapp, it's launching as a 404.

To reproduce:

• Open Flux in a PWA-compatible browser (I'm using MS Edge)
• When prompted, install the app
• Launch the app from a taskbar

The issue looks to be an invalid start_url; it attempts to load https://flux-web.vercel.app/Flux, rather than the root https://flux-web.vercel.app

[vercel[bot]]

Someone is attempting to deploy a commit to a Personal Account owned by @dvmarinoff on Vercel.

@dvmarinoff first needs to authorize it.

[dvmarinoff]

Hi, thanks for the PR! All deployed now.