iOS launch image for the Home Screen app

[HMarzban]

Parent

#249 Deepen the installed PWA.

What to build

Add three apple-touch-startup-image links so an iOS Home Screen launch is not a blank white flash. Android already uses the manifest background_color.

Acceptance criteria

• Three portrait PNGs, logo centered on #ffffff, generated from public/icons/logo-apple-touch.svg (do not reuse the 180px touch icon as the splash):
  • /icons/apple-splash-1290x2796.png — 1290×2796, media (device-width: 430px) and (device-height: 932px) and (-webkit-device-pixel-ratio: 3)
  • /icons/apple-splash-1179x2556.png — 1179×2556, media (device-width: 393px) and (device-height: 852px) and (-webkit-device-pixel-ratio: 3)
  • /icons/apple-splash-1170x2532.png — 1170×2532, media (device-width: 390px) and (device-height: 844px) and (-webkit-device-pixel-ratio: 3)
• _document.tsx links those images. Apple ignores the manifest for this.
• iOS Safari tab (not installed) is unchanged.
• macOS Safari is unchanged.

Out of scope

• Dark splash set
• iPad size matrix
• Landscape set
• Electron or a store app

[HMarzban]

Spec review: three iPhone portrait sizes and paths. Generate from logo-apple-touch.svg. No iPad or dark set.