Icons, back navigation, and theme
ak-icon accepts name: String = 'chevron-right', tone: String = 'primary', and filled: Boolean = false.
Supported names are back, bookmark, search, bell, home, profile, security, settings, device, help, check, and chevron-right. Unknown names fall back safely to chevron-right; the component never loads an arbitrary remote icon.
ak-back-button uses delta: Number = 1 and fallbackUrl: String = '/pages/home/index'. It calls uni.navigateBack when the stack is deep enough, otherwise uni.reLaunch to the fallback. Its touch size is 44×44.
ak-theme-root reads themeState.isDark, applies ak-theme-light or ak-theme-dark, and owns safe-area, page background, and height. Pages continue to use semantic CSS variables instead of hard-coded light/dark colors.