PWA manifest: add id and scope, and give the maskable icon its own padded asset

[MrTig-afk]

The PWA manifest in frontend/vite.config.js (the VitePWA({ manifest: ... }) block) is missing two fields, and the maskable icon entry reuses an unpadded asset.

1. No id

Without an explicit id, the browser derives the app's identity from start_url. If start_url ever changes, the installed app is treated as a different app: users get a second icon on their home screen instead of an update to the one they already installed.

id: '/',

2. No scope

scope currently falls back to the start_url directory. That happens to be correct today, but it is implicit — anything that changes the deploy path changes navigation containment silently.

scope: '/',

3. The maskable icon is the unpadded 512

{ src: '/icon-512.png', sizes: '512x512', type: 'image/png' },
{ src: '/icon-512.png', sizes: '512x512', type: 'image/png', purpose: 'maskable' },

Both entries point at the same file. Android crops a maskable icon to a circle or squircle and only guarantees the inner ~80% safe zone, so an icon drawn to the full canvas loses its edges — and usually its wordmark — on the home screen. A maskable icon needs its own export with the artwork inset into the safe zone.

Suggested fix

• Add id: '/' and scope: '/' to the manifest block.
• Export a separate padded icon-maskable-512.png and point the purpose: 'maskable' entry at it.

Verifying

Chrome DevTools → Application → Manifest shows id and scope once set, and previews the maskable icon inside the safe-zone circle.