Components:
- AlertDialog: Provider, Content (context transition), Action, Cancel + demo
- DropdownMenu: Provider (revelation sound), Content (floating), Item, Separator,
GroupHeading + checkbox/radio indicators via CSS pseudo-elements + demo
- ContextMenu: Provider, Content sharing dropdown-menu visual language + demo
Terra fix — menu variant registry:
- Add menuRegistryByVariant in menu.svelte.ts to track open menus per variant
- MenuMenuState.onOpen() closes all other menus of same variant before opening
- Prevents concurrent context-menus (or dropdown-menus) from being open simultaneously
- Registry lives in terra infrastructure, not air — clean architectural boundary
- Cleanup via onDestroyEffect when component unmounts
CSS fixes:
- DropdownMenu content: z-index: 50 for proper stacking
- Checkbox/radio items: visual indicators via ::before pseudo-elements
- Selectors duplicated for both dropdown-menu and context-menu data-attr prefixes
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>