First-launch onboarding

Step diagram

User taps the app icon
User
First open after install. No saved preference, no signed-in user.
Splash + theme bootstrap
App
App reads prefers-color-scheme synchronously before first paint to avoid the flash of wrong theme.
specs/themes/light-dark.kmd
Locale auto-detect
App
App resolves the device locale and falls back to en-US if no resource matches.
specs/i18n/contract.kmd
Sign-in (optional)
User
User taps KoderSignInButton or skips into a guest session if the app supports it.
specs/koder-app/behaviors.kmd
Lands on home
App
Persisted preferences and user object are now in scope. Navigation back from here exits the app.

Hardcoding ThemeMode.dark before the saved preference is loaded — causes the flash of wrong theme on every cold start.
Showing the home screen before locale resolution finishes — first paint shows raw ICU keys.