Move profile cache to module scope with invalidateProfileCache() and use it in app router to avoid per-navigation DB queries; invalidate the cache on auth changes. Update ProfileSetupScreen and EditProfileScreen avatar pickers to return string choices, add a "remove avatar" option, handle removals (including immediate UI update and backend call in edit flow), and tweak username debounce timing and state. Adjust NotesListScreen app bar layout and icon sizing (leading alignment, actionsIconTheme, wrapped search button) for improved spacing and accessibility.