Add @all mention type that notifies all workspace members (excluding
agents). Includes backend parsing, notification expansion to all members,
and frontend UI with autocomplete suggestion, rendering, and hover card.
Replace all inline avatar implementations (initials divs, Bot icons,
inline img tags) with the shared ActorAvatar component for consistency.
- Extend AssigneePicker with controlled open/onOpenChange, triggerRender,
and align props to support batch toolbar and other contexts
- Replace BatchAssigneePicker (~130 lines) with shared AssigneePicker
- Replace issue-detail sidebar inline DropdownMenu with AssigneePicker
- Add canAssignAgent filtering to issue-detail more menu
- Replace inline avatars in: filter panel, members-tab, agents page,
mention-hover-card, subscribers AvatarGroup
- Add data-slot="avatar" to ActorAvatar for AvatarGroup compatibility
- Add triggerRender prop to PropertyPicker for custom trigger elements
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>