fix(desktop): show a splash while the local backend starts

Re-lands #19706, reverted in #22222 only because it had not been run on a
real desktop build. Without it, the desktop creates no window until its
local backend answers readiness, so a slow startup leaves the app
windowless and Dock clicks do nothing (#23372).

Co-authored-by: Ronak Guliani <ronakguliani@microsoft.com>
Co-authored-by: Julius Marminge <julius0216@outlook.com>
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
caff8dd472ronak-guliani committed on 10/22/2026, 6:06:06 AM· committed by PR Batch Testerparent3b95e78

Checks

All checks passed
3 files changedLine totals unavailable